The Historical Framing Problem: Temporal Modeling of Interactions between Tangible and Intangible Cultural Heritage

5.1.1. Interactions Between Tangible and Intangible Cultural Heritage in Regular Recurrent Events of Long Duration and Ephemeral Events

The first documented Septennial Pilgrimage Procession took place in 1371. Since then, it has reoccurred regularly until the Reformation. This custom was reinstated in 1874 and continued with more or less regular intervals of seven years until today. The Chest of Distress is carried around the streets of Maastricht in these processions as part of a train of relic holders (Figure 4). It is surrounded by all kinds of ephemeral musical and theatrical manifestations.

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Figure 4.

Chest of Distress in the regular recurrent event of the Septennial Pilgrimage Procession in Maastricht. Photo Charles van den Heuvel.

Events of a very ephemeral nature during these processions are, for instance, the swinging of liturgical incense holders. The odors they spread enhance the religious and spiritual experience of the objects carried in the procession.

Apart from these recurrent rites in the public events of the Septennial Pilgrimage Processions or in more private devout practices of the pilgrims, there are regular recurrent events that are unique in content. Since the 20th Century, often a specific theme was attached to the septennial events for which special displays and costumes were designed. For instance, in 1962, after its restoration, the Chest of Distress was carried around again in the septennial procession with the telling theme: Proclaiming the Riches of Christ. The artist Jerôme Goffin designed the costumes and the floats around this theme ⁴ .

Since its first documentation in 1491, the Chest of Distress came several times out of the Basilica of St. Servatius to let the inhabitants of Maastricht say prayers for the protection against wars, epidemics, and other threats to the city (Figure 5).

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Figure 5.

Drawing of two lost marble panels representing the Normans setting fire to the St. Servatius church with praying canons and the Chest of Distress carried around during a state of emergency. Philippe van Gulpen ca.1840, HCL Maastricht (The Netherlands) - LGOG Drawings and Prints LGOG 416.

In the guidelines for the restoration, it was stipulated that the temporarily removed votive heads of around 1450 would be attached to the Chest of Distress again. However, in the final meeting on 5 January 1962, it was suddenly decided not to replace them anymore. The votive heads symbolized the public role of the Chest of Distress, expressing the gratitude of the inhabitants of Maastricht for protecting their city. The esthetic arguments, rather than the original function of the Chest of Distress, had prevailed. The instant decision to remove the votive heads changed the public role and the devotional meaning of the reliquary shrine permanently (Figure 6).

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Figure 6.

Votive heads before (above) and after (below) the restoration of 1962. In the middle restoration drawing by J. Spenger of 1958, with votive heads still present. Instant decision on 5 January 1962 to remove them resulted in a permanent change of the popular function of the Chest of Distress. Composition by Charles van den Heuvel based on photographs Treasury of the Basilica of Sint Servatius, Maastricht (The Netherlands).

It was mentioned above that the bishop’s staff of St. Servatius was removed. It has an important meaning in the iconographic program because it was handed by an angel to Servatius on the authority of God. By removing this staff, this authoritative role became less prominent (Figure 7).

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Figure 7.

Servatius with and without bishop’s staff held by an angel at his right side before and after restoration Treasury of the Basilica of Sint Servatius, Maastricht (The Netherlands).

Furthermore, it was decided to embellish the top of the Servatius’ side with an antique gem that was bought for the occasion (Figure 8). This addition replaced crystal-glass stones that, according to popular belief, had purifying power.

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Figure 8.

Empty setting for missing crystal glass stone (left), Byzantine cameo head added during the restoration of 1962 to embellish the Chest of Distress but with loss of popular meaning. Treasury of the Basilica of Sint Servatius, Maastricht (The Netherlands).

Several ephemeral events take place during pilgrimages not only in the organized urban tour but also in more intimate devotional expressions of pilgrims. Pilgrims visiting the basilica of St. Servatius not only could observe devotional objects but were also allowed to touch them or interact with them in different ways. One of the highlights was drinking from Servatius’ Drinking Cup (for the first time documented in 1433), from which, according to legend, the saint drank himself. It was offered to him by angels sent from heaven during his pilgrimage (Figure 9). The testimony of such an event can be found in the diary of the artisan Arent Willemsz of the northern part of the Netherlands, who visited Maastricht on his pilgrimage to Jerusalem (Koldeweij, 1985; Langereis, 2025). A canon showed the pilgrims the “drinking cup of which Sint-Servaas used to drink, which gave many people health, and we drank from this glass ourselves” (Langereis, 2025, p.17).

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Figure 9.

Ephemeral event of drinking from Servatius’s cup that, according to legend, was handed to him by angels during his pilgrimage. The legend and the custom of pilgrims drinking from it for healing provided new meaning to the Roman drinking vessel of the 1st century (left). Placement of the Servatius’s drinking cup in a chalice during a restoration of 1626/27 for the protection of the object for future use (right). Treasury of the Basilica of Sint Servatius, Maastricht (The Netherlands).

After a mea culpa, mea culpa, they were shown several relics of St. Servatius and “the gilded shrine that in times of disasters was carried around by the canon through town to beg for mercy and the people were blessed with Servatius’ key to heaven”(Langereis, 2025, p.17). The drinking cup was long believed to be from the fourth century, since it was given to the saint during his lifetime (Tagage, 1976). However, during one of its restorations, it came to light that it was actually a Roman drinking cup from the 1st Century A.D. Apparently, many pilgrims drank from it because, around 1625, it was decided to restore the glass cup that had gradually fallen into pieces. At the same time, a painting was commissioned that is not known anymore but had the text: “Effigies scyphi divi Servatii ad vivum anno MDCXXV” (translation: “The image of the cup of Saint Servatius taken from life in the year 1625”) (Koldeweij, 1985, p.220). The restoration took place in the years 1626/27, and the cup was placed in a chalice to protect it. By the end of the nineteenth century, when the Septennial Procession was reinstated, the drinking cup was occasionally made part of the processions (Koldeweij, 1985, p.228). Furthermore, during the daily presentation of some of the reliquaries and sacred cloths from the dwarf gallery of the church, pilgrims were invited to drink from the cup. ⁵ This usage remained in place, and it is reported that in 1918, after so many people had sought protection against the Spanish Flu by drinking from the cup, it needed to be restored. Once again, the restoration came with a new painting. The painting by an unknown Mosan artist represents the cup handed to St. Servatius by angels. In 1935, the cup received a new holder and was placed in a small shrine where it could be seen from all sides (Figure 9). In 1972, the cup was professionally restored in Mainz and, after its return, placed again in the Servatius Basilica Treasury (Koldeweij, 1985).

7.1. Description of the Socio-Cultural Context

In the DH domain, context is often intended to provide the provenance of information. In this sense, HiCO, the Historical Context Ontology (Daquino & Tomasi, 2015) represents contextual information on hermeneutical claims by scholars based on sources’ criticism and interpretation processes. ⁶ Several solutions are provided in the literature to express the provenance of assertions. ⁷ This includes CIDOC-CRM’s E13_Attribute_Assignment class. Among these solutions, CRMinf aims at expressing the scientific process of inference when observing a given situation. It models the researcher’s assumption as a belief, which is considered true or not after the application of the process. Although valuable for the CH domain, we focus on the framing of CH objects in their spatiotemporal context(s), rather than evaluating the outcome of a scientific observation of such interactions.

In this study, the aim is to connect and contextualize cultural artifacts with deeper immaterial aspects of culture. Only a few ontologies have sought to model culture. Although CIDOC-CRM does not provide a further definition of culture, the Visual Resources Association (VRA) Core ontology ⁸ includes a class to describe the culture from which the item originates. The integration of artifacts with the social context is provided by the Semantic Data for Humanities and Social Sciences (SDHSS) extension of CIDOC-CRM (Beretta, 2024). This extension focuses on social representations as systems of values and beliefs. These systems are modeled as collections of propositional objects, types, and information objects that represent the content of social representations of a given group. The Art and Architectural Argumentation Ontology (AAAo) ⁹ allows to represent social facts as negotiated and agreed-upon knowledge within a community, whose status can change over time. Although it is a valuable model for expressing the values and meaning of CH objects for certain communities, it considers only time-related variations in an agreement status, and not place. Both are necessary in cross-cultural contexts. Further ontologies that address the topic of cultural values are ValueNet (Asprino et al., 2024; De Giorgis et al., 2022) and ICON, an ontology for artistic interpretations (Sartini et al., 2023). ValueNet addresses the description of moral and social values towards the modeling of commonsense knowledge. Following Fillmore’s frame theory (Fillmore, 2008) and DOLCE’s Description&Situation ODP, it models societal values as abstract descriptions, which then occur in concrete situations. In the current project, the class CulturalValue of ValueNet may be used to further describe how abstracts concepts (e.g., religious concepts) are expressed in certain cultures related to the CH object under observation. The ICON ontology, developed in the domain of art history, offers means to model the subjects and meanings recognized in artworks in the form of interpretations on various levels of depth. At the deeper level of interpretation, the class icon:CulturalPhenomenon, and its subclasses, allow us to express in more detail socio-cultural phenomena that artifacts carry according to cultural-historical interpretations.

Another aspect relevant to the modeling is the function that a CH object acquires in different socio-cultural contexts or events. Several ontologies and ODPs have been proposed to represent the variation of roles taken on by people over time (Goy et al., 2018; Peroni et al., 2012; Presutti et al., 2008). CIDOC-CRM suggests modeling a change of an object‘s function through an E7_Activity in which the object is used. ¹⁰ However, this solution does not seem suitable for indicating a more general use of the object that recurs in multiple situations. It also does not indicate how the function should be represented. Two further properties allow to indicate the intended use of an object (e.g., a glass has as its intended use “drinking”) or a use it acquired in a second place through, respectively, the properties crm:P101_had_as_general_use and crm:P103_was_intended_for. To the best of the authors’ knowledge, the only model addressing a change of function is the AAAo ontology. Through the class ZE5_Function_Status, it is possible to express that, according to a community, in a specific time period or event, the object acquires a specific function.

7.2. Framing the Object in Its Context(s)

In the context of this work, frames are in, the first place, intended to temporarily isolate objects or phenomena and their contexts to observe them in more detail. They are used to observe historical events. Several ontologies address observation as an object of study. Among them, the CRMsci extension of the standard CIDOC-CRM ¹¹ focuses on scientific observation in various fields, including the conservation of CH. In particular, the class S4_Scientific_Observation represents the act of capturing scientific knowledge about physical phenomena (e.g., the observation of light absorption in paintings). As its emphasis is merely on quantitative measurable data and validation in concrete applications, the CRMsci extension is considered less suitable to frame a CH object in its socio-cultural context(s).

More relevant among foundational ontologies is the Description&Situation pattern included in the foundational ontology DOLCE. ¹² The description of this pattern defines concepts to create views on “relational contexts” from a set of observations (Gangemi & Mika, 2003). The DnS ODP relies on Minsky’s and Fillmore’s frame semantics theory (Fillmore, 2008; Lazzari et al., 2024; Minsky, 1974; Sullivan, 2023).

With the intended usage of frames in mind to observe interacting storylines of objects in context(s) from historical perspectives, the CIDOC-CRM class crm:E92_Spacetime_Volume is relevant. Its subclass E4_Period interestingly describes periods having their own identity. However, the inclusion of space together with time in the scope note and its dependency from crm:E2_Temporal_Entity results in not clarified relations between spacetime and perdurants in the model (see Section 4). ¹³ Nevertheless, the crm:E92_Spacetime_Volume class is included because it meets the description of historical frames. Therefore, it is recommended to redefine the class E4_Period. Being a high-hierarchy class focusing foremost on physical things, E4_Period should be further enhanced to encompass the changes in interactions between the cultural objects and their contexts. Spacetime aspects of CIDOC-CRM are treated in more detail in CRMgeo, a module that specializes CIDOC-CRM’s Spacetime volume to be related to geographical coordinates. As the scope of the current work includes the concept of spacetime in more abstract terms than what is discussed in CRMgeo, we refer, in this work, to the Spacetime Volume class as defined in CIDOC-CRM. For the reason that the CRMgeo extension extends the same class of Spacetime Volume, as historical frames do, it could be used in principle to extend them with GIS coordinates. However, defining spatial coordinates is out of the scope of this work.

7.3. Time, Space, and Spacetime in CIDOC-CRM and Foundational Ontologies

As introduced in Section 3.1, the unity of spacetime in the observation of cultural and art historical phenomena is particularly relevant. After all artifacts in different geographical areas (e.g., Italy, the Netherlands) consistently vary in the same time period (Panofsky, 2004). Nevertheless, some foundational ontologies, such as the Unified Foundational Ontology (UFO), the Basic Formal Ontology (BFO) (Arp et al., 2015), and DOLCE, provide a fundamental distinction between endurants, namely objects defined in space that maintain their identity over time, and perdurants, whose identities are defined by the participation of those objects in a moment of time (i.e., events) (Gangemi et al., 2002). This distinction is represented 1) in DOLCE through dul:Object (endurant) and dul:Event (perdurant), 2) in BFO through Continuant (endurant) and Occurrent (perdurant), and 3) in UFO through the modeling of two ontologies, UFO-A and UFO-B, respectively, concerning endurants and perdurants. CIDOC-CRM, the standard for the CH domain, represents perdurants as a crm:E2_Temporal_Entity and its subclasses, and endurant as a crm:E77_Persistent_Item. A relation between them is established through the property crm:P12_occurred_in_the_presence_of with E5_Event, subclass of E2, and E77.

BFO defines its entities as relating not only to time but also to space through a unity of spacetime regions. In particular, they define processes as “a temporally extended continuum, a spacetime worm, stretched out in and through the single unified container that is the entirety of spacetime” (Galton, 2018). Time regions are defined as the projection of spacetime regions on the temporal dimension. Although the ontology is intended to be applied mainly to the biological domain, the unity of spacetime in its formalization is of interest for the modeling of spacetime in the current paper.

A similar conception of unity of space and time appears in CIDOC-CRM through the top-level class E92_Spacetime_Volume. It is intended to represent the spatiotemporal extensions of phenomena. Although valuable, the introduction of this class in more recent versions of the ontology contains some unclarified relations with the definitions of perdurants and endurants. These definitions are not discussed in relation to spacetime unity. This might result in some inconsistencies. In particular, the classes E4_Period and its subclass E5_Event are defined as subclasses of both E92_Spacetime_Volume and E2_Temporal_Entity, the latter defined as a perdurant in relation to the sole temporal dimension. ¹⁴ DOLCE defines the space and time of objects as qualities that can vary (Galton, 2018). Time and space are abstract regions to which the space and time qualities of objects refer separately. In short, they are not considered as a unity of time and space. As underlined by Bai and Grüninger (2023), the problem of a representation of spacetime unity in ontologies remains an open and challenging one.

7.4. Tangible and Intangible Cultural Heritage

The models developed in the context of the conservation and restoration subdomains of CH are intended to support professionals in their practice. However, they are less suitable for describing the impact of decision-making in removing or adding parts of physical objects on the changes in function and evolution of meaning of restored works in context.

In the above, it was argued that the methods and tools directed at intangible CH practices are still oriented toward objects and focus on the preservation of material-based knowledge (Hou et al., 2022). This is still reflected in existing ontological models. Most models of intangible CH deal with temporal aspects in musical genres or dance movements separately. However, they do not address the interactions over time between material and immaterial cultural expressions (Lombardo et al., 2016; Skaug & Aalberg, 2024). The Drammar ontology describes the core features of drama plays, including tangible and intangible aspects. Other models concern spatiotemporal statements regarding the physical presence of artists and exhibitions (Carboni, 2025; Rodríguez-Ortega, 2024). The same applies to the Library Reference Model (LRMoo) ontology, the CIDOC-CRM extension that expresses the Functional Requirements for Bibliographic Records (FRBR) model. This ontology has the interesting F31 Performance class that includes performing multiple individual works combined into a program (Bekiari, Doerr, et al., 2024). The Septennial Pilgrimage Procession in the case study would, in principle, fit in that class. However, since performance in this ontology is always associated with an instance F1 Work intended for describing artistic creations (e.g., theatrical plays, a musical work, or a choreographic work), it is less suitable for describing ephemeral events of a religious-popular nature, such as religious processions.

Particularly relevant for the modeling of the temporal characteristics of ephemeral events are two studies that discuss the development of ODPs representing recurrent social situations or events, as immaterial practices that often recur over time. These ODPs, based on the famous horse races held twice a year between the “contrade” of Siena, the Palio (Carriero et al., 2021), and on the Umbria Jazz festival (Carriero et al., 2019), describe well-defined, regularly recurrent events over a long period of time. They exclude, therefore, irregularly occurring events with fuzzy and ephemeral boundaries. Nevertheless, the Art and Architecture Thesaurus (AAT) of the Getty Research Institute provides helpful definitions for ephemeral art forms and temporary structures used in intangible CH. ¹⁵ Fuzzy descriptions of time periods can be represented through the Extended Date/Time Format (EDTF) Specification created by the Library of Congress. ¹⁶ In particular, the qualifiers expressing uncertainty, approximation, and open-ended periods are useful in the context of the description of uncertainty related to ephemeral events (see Section 8.4). Nevertheless, the specification is not compatible with the XSD time format used as a standard for RDF data. This issue is addressed by the EDTF Ontology, ¹⁷ which allows the description of temporal entities with the EDTF specification (Shaw, 2022) by extending the Time Ontology. ¹⁸

Currently, no ontology addresses the problem of framing in an encompassing way a CH object in the interaction with its socio-cultural context. Only separate modeling solutions are offered for parts of the issue. Attention has been given to the interpretation act (HiCO, ICON) of certain facts and on the scientific observation and inference processes (CRMsci, CRMinf). However, the question of isolating meaningful relations between material and immaterial CH practices to represent their interactions and modifications over time has not been addressed yet. ValueNet, AAAo, and SDHSS merely focus on the descriptions of socially or culturally relevant facts. However, they do not provide the means to frame these contextual facts together with the cultural objects in space and time. For the concept of framing as intended in this work, the representation of a part of the spacetime is relevant. Nevertheless, the topic is addressed in current ontologies only in relation to concrete applications in georeference systems (CIDOC-CRM’s Spacetime Volume and the CRMgeo Extension). For this reason, the current work aims at filling this gap by providing means to describe material and immaterial CH interactions and their evolution through the spacetime continuum.

The Object in Situation module (See Figure 10 and Tables 3 to 5 ²¹ ) addresses the group of requirements R1, concerning the function of the object in relation to a context and/or immaterial practices. To this aim, it is based on the theoretical model of Anderson illustrated in Section 3. This describes the object within the belief system that gives it its specific functions and meanings. It reuses the solution proposed by the AAAo ontology to represent the function ascribed to an object by a community, namely, the class aaao:ZE5_Function_Status and its related properties. This class represents the function as an institutional fact of a temporal nature. The object acquiring the function is specified through the property aaao:ZP14_has_functional_subject. The function is ascribed through aaao:ZP15_ascribes_function, which associates an instance of crm:E55_Type. As the model does not offer a distinction between a practical and a social function, stated in the Anderson’s model, we introduce a class Function, subclass of crm:E55_Type, and two subclasses, :PracticalFunction and :SocialFunction. They represent respectively social and practical functions. Another extension proposed is the relation :hasFunction, intended as a shortcut of the longer path associating the function to the object through the aaao:ZE5_Function_Status class. Further information can be described by reusing properties inherited from the superclass aaao:ZE1_Institutional_Fact. The relation aaao:ZP4_holds_for indicates the community for which the indicated status holds (e.g., the healing function of St. Servatius cup holds for the community of Catholics).

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Figure 10.

Module expressing a function an object acquires during a specific cultural event or in events repeated over time in a historical frame. New classes are marked in yellow. Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

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Table 3.

Newly Added Classes of the Object in Situation Module (Module 1).

Class	Alignment	Description
:ObjectInRecurrentEvent	subclass of dul:Situation, dul:Collection	Situations including a CH object and an event repeated over time, either in regular or irregular intervals, presenting unifying characteristics
:ObjectInRecurrent IrregularEvent	subclass of :ObjectInRecurrentEvent	A situation grouping events in which the same object participates having similar, unifying characteristics over time (e.g., function)
:ObjectInRecurrent RegularEvent	subclass of :ObjectInRecurrentEvent; owl:sameAs res:RecurrentEventSeries	A situation in which unifying characteristics of events regularly recurring over time are identified, and the time interval with which they are repeated can be indicated
:Function	subclass of crm:E55_Type	A class identifying the function that an object acquires
:PracticalFunction	subclass of :Function	A class identifying the practical function that an object acquires (e.g., the “drinking” function of a vessel)
:SocialFunction	subclass of :Function	A class identifying the socially attributed, non-strictly practical function that an object acquires (e.g., the healing function of St. Servatius cup in a catholic context)

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Table 4.

Reused Classes in the Object in Situation Module (Module 1).

Class	Description
aaao:ZE5_Function_Status	“An instance of function status is the collective ascription of an operative functionality to an object by a community. The substance of the function status is the communal commitment to relating to and / or using the object in question according to a designated function.” (Bruseker et al., 2025)
crm:E74_Group	“This class comprises any gatherings or organizations of human individuals or groups that act collectively or in a similar way due to any form of unifying relationship.” (Bekiari, Bruseker, et al., 2024)
crm:E5_Event	“This class comprises distinct, delimited and coherent processes and interactions of a material nature, in cultural, social or physical systems, involving and affecting instances of E77 Persistent Item in a way characteristic of the kind of process. Typical examples are meetings, births, deaths, actions of decision taking, making or inventing things, but also more complex and extended ones such as conferences, elections, building of a castle, or battles.” (Bekiari, Bruseker, et al., 2024)
res:TimePeriod	Class indicating the “time period that has typically to elapse before the next event is held, which is usually approximate (e.g., yearly, monthly, etc.), and is different from the actual time between two events, which can be derived from the time intervals computed between any two members”(Carriero et al., 2019).
dul:EventType	“A Concept that classifies an Event. An event type describes how an Event should be interpreted, executed, expected, seen, etc., according to the Description that the EventType isDefinedIn (or used in)” (source: ontology file)
:HistoricalFrame	Class, defined in the Historical Frame module, which represents the socio-cultural context in space-time that is the context of the observed object.

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Table 5.

Properties of the Object in Situation Module (Module 1).

Property	Domain	Range	Description
Newly added properties				:includesEvents OfType	:ObjectIn Situation;	dul:EventType	Relate the event series with the type of event that is included (e.g., mass, procession). It is a property chain for :hasMemberEvent o dul:hasEventType.
:hasMemberEvent	:ObjectIn RecurrentEvent	dul:Event	Property to indicate the events of a series based on the model of the Recurrent Situation and Recurrent Event Series ODPs, which property cannot be directly reused as they have a different domain.
:includesFact	:ObjectIn RecurrentEvent	aaao:ZE1_ Institutional _Fact	Property expressing the fact that the indicated institutional fact (for example, the fact that the CH object holds a function) is observed in the situation that represents a series of events repeating over time.
:hasFunction	crm:E1_Entity	crm:E55_Type	Property expressing the function that a CH object has. It is a shortcut for the longer path aaao:ZE5_Function_Status aaao:ZP14_has_functional_subject crm:E1_Entity; aaao:ZP15_ascribes_function crm:E55_Type. It is declared as subroperty of crm:P2_has_type and as a superproprerty of crm:P103_was_intended_for and crm:P101_had_as_general_use, which add more detail to the usage or function that the object has.
Reused properties
aaao:ZP14_has_ functional _subject	aaao:ZE5_ Function_Status	crm:E1_Entity	“This property is used to indicate the entity for which a certain functional classification is taken to hold by the instance of functional status.” (Bruseker et al., 2025)
aaao:ZP15_ ascribes _function	aaao:ZE5_ Function_Status	crm:E55_Type	“This property is used to indicate the type of function which is indicated as holding for the subject of the function status.” (Bruseker et al., 2025)
aaao:Z75_applies_ for_context	aaao:ZE1_ Institutional _Fact	crm:E5_Event	“This property is used to indicate an event context which limits the temporal scope within which an instance of institutional fact is meant to hold. When indicated the event context stands as the frame in which the institutional fact is held to be valid by the associated group for whom it has significance.” (Bruseker et al., 2025)
aaao:ZP4_holds _for	aaao:ZE1_ Institutional _Fact	crm:E74_Group	“This property is used to indicate the community or group for whom an instance of institutional fact holds. Institutional facts have identity only relative to some group for whom they have a significance as formulated through a chosen symbolic system.” (Bruseker et al., 2025)
rss:has Unifying Factor	dul:Collection	owl:Thing	Property relating a collection to the recognizable patterns shared by all the members of a series, unifying them. For a more detailed description, see Carriero et al. (2021)
res:hasTime Period	res:Recurrent EventSeries	res:TimePeriod	Property relating a recurrent event series to the time frequency with which it occurs. (Carriero et al., 2019)
:hasContext	crm:E1_Entity	:Historical Frame	Property defined in the Historical Frame module to relate the observed object, or the situations and events in which it appears, to a Historical Frame. In this context, it is reused to express the frame in which the function status is considered being valid, in a broader sense than the property aaao:Z75_ applies_for_context, as it does not force to specify a specific event in which the function occurs.

In the module, the context in which the function is observed can be specified with different levels of detail, namely, as a spatiotemporal frame, a single event, or a series of events recurring over time. The first option describes the context in a wide sense by using the class :HistoricalFrame. This is explained in more detail in the following module. The function status can be related to the historical frame through the relation :hasContext. If the function is recognized only in the occasion of a specific event, the property aaao:Z75_applies_for_context, relating the status to an event, can be used. Finally, the status can be related to events recurring over time through the property :includesFact, which connects the newly added class :ObjectInRecurrentEvent, explained below, with the function status acquired.

The class :ObjectInRecurrentEvent is introduced to represent situations collecting events that are repeated over time and share the same characteristics, such as the Septennial Pilgrimage Processions. For this reason, it is declared a subclass of dul:Situation and dul:Collection, following the modeling solution provided by Carriero et al. (2019, 2021). The property :includesEventsOfType specifies the unifying type of events included in the collection (e.g., “procession”). The class is then further specialized in two subclasses, namely :ObjectInRecurrentIrregularEvent and :ObjectInRecurrentRegularEvent. Whereas a regular time interval in which the event is repeated over time can be specified for the latter, the former has no predictable time constraints related to it. As the latter class presents characteristics similar to the Recurrent Event Series pattern (Carriero et al., 2019), alignments and the reuse of some classes and properties (e.g., rss:hasUnifyingFactor) are provided. The Recurrent Event Series pattern is preferred over the Recurrent Situation Series pattern, as the class dul:Event seems more suitable to describe the occurrence of CH events such as religious processions that were held in the past. Furthermore, the class dul:Event can be aligned with crm:E5_Event, which facilitates the use of different ontologies in the same descriptive framework. The cited ODPs (Carriero et al., 2019, 2021) allow expressing immaterial practices recurring only regularly over time. Therefore, they only partially fulfill the requirement of describing various types of repetitions of immaterial CH practices (uniqueness, irregular and irregular repetitions). For this reason, we partially repeated and extended the modeling to encompass other types of recurrence.

The Historical Frame module, presented in Figure 11 and Tables 6 and 7, is intended to relate the object under observation to the cross-cultural system. We identified such a system in Anderson’s model and included it in the historical frame definition provided in Section 4. Furthermore, it is addressed in the group of requirements R2. Mostly based on CIDOC-CRM, it integrates a class from the ICON ontology, namely icon:CulturalPhenomenon and its subclasses icon:Belief, icon:Tendency, icon:CulturalValue, and icon:Attitude. ²²

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Figure 11.

Module extending CIDOC-CRM and ICON to represent an historical observation Frame which put in relation observed CH objects with immaterial, socio-cultural aspects coexisting in spacetime and influencing the object. Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

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Table 6.

Classes of the Historical Frame Module (Module 2).

Class	Description
Newly added classes
:HistoricalFrame subclass of crm:E92_Spacetime_Volume	The Historical Frame captures the space-time continuum to relate the observed CH object(s) to socio-cultural characteristics of the same context(s). It captures a portion of spacetime in which the CH object coexisted with immaterial, cultural traits that interacted with them.
:Culture owl:sameAs sdhss:C26_Representation	Fuzzy class to indicate the broad concept of culture of which the frame observes some features (e.g., Belief that St. Servatius drunk from the drinking cup).
Reused classes
crm:E53_Place	“This class comprises extents in the natural space where people live [ ⋯ ] They may serve describing the physical location of things or phenomena or other areas of interest.” (Bekiari, Bruseker, et al., 2024)
crm:E52_Time_Span	Abstract temporal extents, having a beginning, an end, and a duration. No semantic connotations are attributed to them.
icon:CulturalPhenomenon	“The cultural phenomenon entity expresses the cultural, social, and historical aspects of which the work of art can be a document.” (Bekiari, Bruseker, et al., 2024)
icon:Belief	Specification of a cultural phenomenon as a belief
icon:Attitude	Specification of a cultural phenomenon as an attitude
icon:CulturalValue	Specification of a cultural phenomenon as a cultural value
icon:Tendency	Specification of a cultural phenomenon as a tendency

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Table 7.

Properties of the Historical Frame Module (Module 2).

Property		Description
Newly added Properties
:hasContext	crm:E1_Entity	:HistoricalFrame	Relation between objects, events or situations in which they participate, and a :HistoricalFrame which identifies the socio-cultural context in which the object existed
:hasCreation_Context	crm:E1_Entity	:HistoricalFrame	Subproperty of :hasContext to specifically express that the object examined is related to the cultural context in which it was created (e.g., “Roman culture” is the creation context of the Roman cup created in I Century)
:includescultural_ Trait	:Historical Frame	icon:Cultural Phenomenon	The property relates a Historical Frame with the immaterial traits of a culture that are relevant for the understanding of the objects.
:refersToCulture	:Historical Frame	:Culture	Relation of historical frame to the fuzzy culture it observes.
:motivates	crm:E1_Entity	crm:E1_Entity	Generic relation that expresses that an entity motivates the existence or characteristics of another one (e.g., the belief that St. Servatius drunk from the cup motivates the healing function of the cup)
:believedThing	icon:Belief	crm:E1_Entity	A relation specifying the thing believed in the belief system of the culture in question.
Reused properties
crm:P10_falls_ within	crm:E92_ Spacetime_Volume	crm:E92_ Spacetime_Volume	“This property associates an instance of E92 Spacetime Volume with another instance of E92 Spacetime Volume that falls within the latter. In other words, all points in the former are also points in the latter. This property is transitive and reflexive” (Bekiari, Bruseker, et al., 2024)
crm:P132_ spatiotemporally _overlaps_with	crm:E92_ Spacetime_Volume	crm:E92_ Spacetime_Volume	“This symmetric property associates two instances of E92 Spacetime Volume that have some of their extents in common.” (Bekiari, Bruseker, et al., 2024)
crm:P133_ spatiotemporally _separated_from	crm:E92_ SpacetimeVolume	crm:E92_ SpacetimeVolume	“This symmetric property associates two instances of E92 Spacetime Volume that have no extents in common.” (Bekiari, Bruseker, et al., 2024)
crm:P161_has_ spatial_projection	crm:E92_ SpacetimeVolume	crm:E53_Place	“This property associates an instance of E92 Spacetime Volume with an instance of crm:E53_Place that is the result of the spatial projection of the instance of the E92 Spacetime Volume on a reference space.” (Bekiari, Bruseker, et al., 2024)
crm:P160_has_ temporal_projection	crm:E92_ SpacetimeVolume	crm:E52_Time_Span	“This property describes the temporal projection of an instance of E92 Spacetime Volume.” (Bekiari, Bruseker, et al., 2024)

The module is centered around the class :HistoricalFrame, which isolates a part of the spacetime continuum to frame the socio-cultural context of the object(s) under observation. In this way, it captures the space-time continuum to connect observed cultural object(s) with socio-cultural characteristics of the same context(s). The class is declared as a subclass of CIDOC’s E92_Spacetime_Volume. ²³ Every object under observation is related to a Historical Frame through the relation :hasContext. The subproperty :hasCreationContext distinguishes the Historical Frame in which the artwork was created from the following ones (e.g., the Roman cup has as creation context the frame referring to the Roman culture). The domain of the property is deliberately broad to allow for the inclusion of the object, the events, and the situations in which the object participates. These situations can be related to different cultural contexts.

The properties inherited from E92_Spacetime_Volume express relations between the frames (Requirement R2.4). These are inclusion (crm:P10_falls_within), overlap (crm:P132_spatiotemporally_overlaps_with) and separation (crm:P133_spatiotemporally_separated_from).

A Historical Frame can express the traits of a specific or multiple culture(s) (:Culture) characterizing it through the relation :refersToCulture and establishing a relation with specific aspects (relation :includesCulturalTrait; requirement R2.2). As culture is a fuzzy concept, the boundaries of which are usually not well defined and stable over time (Burke, 2005), frames are used to isolate and identify traits that are relevant for making meaningful observations of the object. These are known to be present for the duration of the spacetime volume identified by the frame.

Finally, the module is integrated with further properties. The property :believedThing enriches the class icon:Belief by relating it to the actual content believed. Furthermore, the property :motivates serves to underline the influence of particular cultural traits or events on other objects.

The proposed modeling allows us to frame the context(s) of the CH object with different levels of granularity (requirement 2.4). For instance, the Historical Frame can identify periods in which cultural traits are recognized over long periods of time such as the religious culture of Maastricht from the Middle Ages till today. However, the Historical Frame can also be subdivided into smaller ones. These subdivisions allow for grouping more specific aspects of the culture in that period, such as the mentioned ephemeral expressions in Maastricht in the year 1962. Such smaller frames may include specific cultural traits and events that are not necessarily represented in the larger historical frame. In this way, the historical frame reflects two of the three types of observations defined in the GA storyline model (van den Heuvel & Zamborlini, 2021) presented in 4.3. Historical Frames with a long duration over time and space (e.g., the Frame observing the culture of Maastricht from the 14th Century to today) combine the contextual traits that are always true for the whole considered period. The Historical Frame in this form is a kaleidoscopic view over the storylines of the objects and their contextual immaterial features (e.g., devotion for the Chest of Distress). At the same time, the relationship crm:P10_falls_within allows one to identify shorter periods. They can be observed in a 2D, synchronous view of a specific moment in time (e.g., the slice of spacetime of the procession in Maastricht in 1962).

Furthermore, single separated frames, or on the contrary, multiple overlapping frames can be recognized. For example, the historical frames of the thematic processions that occur uniquely include special features (e.g., temporary constructions, plays written for the occasion) that vary from time to time. Such frames do not overlap with each other but fall within the overall frame of the culture of Maastricht, in which the recurrent traits of the Chest’s procession are also included. Cultural events can also be observed in a wide overlapping frame that encompasses separate frames such as the alternate use of liturgical objects by two completely different religious communities (e.g., the Catholic and the Protestant ones, in the same place and period). ²⁴

Historical Frames must not be confused with Reference Frames. The latter deal with common sense pre-knowledge used by the observing agent. This resembles the definition of dul:Description. This definition also represents the background knowledge of the observer in interpreting the object. This knowledge can be very generic but also very detailed, for instance, when dealing with interpretations of an expert based on domain knowledge.

The module to express the evolution of material and immaterial objects and their functions (group of requirements R3) combines AAAo with CIDOC-CRM and GA Storylines. It describes three types of evolution, namely the evolution in function and in the material and immaterial aspects of the object in question (Figure 12 and Tables 8 and 9).

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Figure 12.

Module to describe the evolution of the functions of the object and its material and immaterial aspects. Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

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Table 8.

Newly Added Classes and Properties of the Evolution Module (Module 3).

Class	Description
Newly added classes
:ConceptualVariation subclass of crm:E7_Activity	The class identifies an activity that modifies immaterial visual traits of a CH object, such as the subject depicted, creating two versions of the immaterial object, which correspond to the version preceding the intervention and the one resulting from it.
Reused classes
aaao:ZE5_Function_Status	See the definition provided in Table 4
crm:E52_Time-Span	“This class comprises abstract temporal extents, in the sense of Galilean physics, having a beginning, an end, and a duration.” (Bekiari, Bruseker, et al., 2024)
crm:E5_Event	see the definition provided in Table 4
crm:E36_Visual_Item	“This class comprises the intellectual or conceptual aspects of recognisable marks, images and other visual works” (Bekiari, Bruseker, et al., 2024)
crm:E11_Modification	“This class comprises instances of E7 Activity that are undertaken to create, alter or change instances of E24 Physical Human-Made Thing.” (Bekiari, Bruseker, et al., 2024)
crm:E80_Part_Removal subclass of crm:E11_Modification	“This class comprises the activities that result in an instance of E18 Physical Thing being decreased by the removal of a part.” (Bekiari, Bruseker, et al., 2024)
crm:E79_Part_Addition subclass of crm:E11_Modification	“This class comprises activities that result in an instance of E18 Physical Thing being increased, enlarged or augmented by the addition of a part.” (Bekiari, Bruseker, et al., 2024)
crm:E24_Physical_Human-Made_Thing	“This class comprises all persistent physical items of any size that are purposely created by human activity.” (Bekiari, Bruseker, et al., 2024)
crm:E55_Type	“This class comprises concepts denoted by terms from thesauri and controlled vocabularies used to characterize and classify instances of CIDOC CRM classes.” (Bekiari, Bruseker, et al., 2024)
ga:Storyline	“Storyline is a UFO:ComplexEvent that can be split into (i) ga:Object-Storyline, which is composed of participations of a single UFO:Object, and (ii) ga:Bundle-Storyline (Kublers’ “fibers of duration”), in which two or more UFO:Objects participate.” See the UML model of Storylines defined in van den Heuvel and Zamborlini (2021)

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Table 9.

Properties of the Evolution Module (Module 3).

Property	Domain	Range	Description
Newly added properties
:conceptually Modifies	:Conceptual Variation	crm:E36_Visual_ Item	The property relates the :Conceptual Variation to the Visual Item it modifies, i.e., the version of the work before the intervention.
:createsConceptual Version	:Conceptual Variation	crm:E36_Visual_ Item	The property relates the :ConceptualVariation to the Visual Item version resulting from the intervention.
:createsPhysical Version	crm:E11_ Modification	crm:E24_Physical_ human-made_Thing	The property relates the crm:E11_Modification to the physical version resulting from the intervention.
:manifestsIn	crm:E24_Physical_ human_made_Thing	crm:E24_Physical_ human_made_Thing	The property relates a CH artifact to the physical versions that are created by a physical act that consistently modifies the artifact but without affecting its identity. It is the result of the action of a crm:E11_Modification that generates a new version of the item (and not a fully new item).
Reused properties
aaao:ZP113_has_ successor_ status	aaao:ZE1_ Institutional_ Fact	aaao:ZE1_ Institutional_ Fact	“This property links one instance of institutional fact with another where the latter succeeds the former as a formal continuation.” (Bruseker et al., 2025)
aaao:ZP111_ initiated	crm:E5_Event	aaao:ZE1_ Institutional_ Fact	“This property is used to connect the instance of event to the instance of institutional fact which it brought into existence by fiat thanks to its accordance to a socially defined norm.” (Bruseker et al., 2025)
dul:precedes	dul:Entity	dul:Entity	“A relation between entities, expressing a ‘sequence’ schema.”
crm:P65_shows_ visual_item	crm:E24_Physical_ Human-Made_Thing	crm:E36_Visual_ Item	This property documents an instance of E36 Visual Item shown by an instance of E24 Physical Human-Made Thing. In the current model, it is used to relate the physical part of the object to the immaterial, visual one.
crm:P31_has_ modified	crm:E11_ Modification	crm:E18_Physical_ Thing	“This property identifies the instance of E18 Physical Thing modified in an instance of E11 Modification.” (Bekiari, Bruseker, et al., 2024) It is superproperty of crm:P110_augmented and crm:P112_diminished.
crm:P110_ augmented	crm:E79_Part_ Addition	crm:E18_Physical_ Thing	“This property identifies the instance of E24 Physical Human-Made Thing that is added to (augmented) in an instance of E79 Part Addition.” (Bekiari, Bruseker, et al., 2024)
crm:P113_ removed	crm:E80_Part_ Removal	crm:E18_Physical_ Thing	“This property identifies the instance of E18 Physical Thing that is removed during an instance of E80 Part Removal activity.” It is subproperty of crm:P112_diminished. (Bekiari, Bruseker, et al., 2024)
crm:P112_ diminished	crm:E80_Part_ Removal	crm:E18_Physical_ Thing	“This property identifies the instance of E18 Physical Thing that was diminished by an instance of E80 Part Removal.” (Bekiari, Bruseker, et al., 2024)
crm:P111_added	crm:E79_Part_ Addition	crm:E18_Physical_ Thing	“This property identifies the instance of E18 Physical Thing that is added during an instance of E79 Part Addition activity.” (Bekiari, Bruseker, et al., 2024)
crm:P12i_was_ present_at	crm:E77_Persistent_ Item	crm:E5_Event	“This property describes the active or passive presence of an E77 Persistent Item in an instance of E5 Event without implying any specific role.” (Bekiari, Bruseker, et al., 2024) In this context, it is reused to indicate the participation of an object (endurant) in a storyline (perdurant).
crm:P4_has_ time-span	crm:E2_Temporal_ Entity	crm:E52_Time-Span	“This property associates an instance of E2 Temporal Entity with the instance of E52 Time-Span during which it was on-going.” (Bekiari, Bruseker, et al., 2024)

To represent the change of function, the class aaao:ZE5_Function_Status, introduced in module 8.1, is reused. Being defined as a temporal entity, the evolution of the function can be expressed by declaring multiple instances of the class. Each instance can be associated with a different time-span. The instances are indicated by the chronological order in which they occur through the relation aaao:ZP113_has_successor_status (Requirement R3.1).

The physical evolution of the cultural object is represented by reusing and extending CIDOC-CRM. The activities determining a physical change of the object are already addressed by the model, namely: crm:E11_Modification and the subclasses part addition (crm:E79) and part removal (crm:E80). E79 and E80 indicate that a physical part that was added or removed from the object (respectively, through the relations crm:P111 added and crm:P113 removed), augments or diminishes (crm:P110_augmented/crm:P112_diminished) the same object, without changing its identity. For this reason, the intervention does not create a new instance of the object. ²⁵ As a consequence, CIDOC-CRM does not provide a solution for modeling different versions of the object when its identity is preserved. This is because modifications (parts addition and removal) act on the same instance. To solve this problem and to allow for the identification of different versions, the property :manifestsIn is newly introduced. It relates the same physical object to multiple physical versions of it. This makes it possible to provide more details for each version (e.g., corresponding immaterial versions) as proposed in a previous study (Baroncini et al., 2026). Furthermore, we introduce the property :createsPhysicalVersion that indicates the version of the object created after the physical intervention.

Nevertheless, an extension is needed to register immaterial changes that affect the immaterial part of the object, namely, the visual representation (crm:E36_Visual_Item). CIDOC-CRM provides only the class crm:E65_Creation to indicate an activity that leads to the creation of a conceptual item. However, such class implies that there is no continuity in the identity of the object, similarly to the E81_Transformation class described above. To solve this problem and to provide a versioning of the visual, immaterial stages of the CH object, a class :ConceptualVariation is introduced, modifying (:conceptuallyModifies) a previous version and creating a new one (:createsConceptualVersion), as a subclass of crm:E7_Activity. Being subclasses of crm:E5_Event, the physical interventions described above and the :ConceptualVariation can be indicated as those activities initiating a new functional status through the property aaao:ZP111_initiated (requirement R3.2). The property dul:precedes is reused to indicate the sequence in which the two Visual Items occur. As a Visual Item is not a temporal entity, there is no available property in CIDOC-CRM to indicate an order between these two items. Instead, this is addressed by the reused DOLCE property.

In this way, CIDOC-CRM’s domain-specific representations of modifications of CH can be combined with the AAAo description of a function status to describe both (im)material and functional changes of a CH by proposing a minimal extension only.

The evolution of material and immaterial variations of the object can be modeled by reusing the GA model of storylines (van den Heuvel & Zamborlini, 2021) (requirement R3.1). The storyline is defined herein as a chain of events (perdurants) in which the observed CH object participates. Although not yet formalized in OWL (see future work), the model is reused here to trace the temporal evolution of objects. As storylines can encompass all objects that have a persistent identity throughout time (i.e., endurants), all material and immaterial entities can be included in a storyline by reusing the relation crm:P12i_was_present_at. The same applies to the events in which the object participates, corresponding, in the proposed module, to the subclasses of crm:E7_Activity (i.e., :ConceptualVariation, crm:E79, crm:E80, crm:E81), for which the property crm:P9_consists_of is used. ²⁶

Nevertheless, some issues arise when aligning aaao:ZE5_Function_Status to the model. In fact, both the storylines and the views traversing them are defined as complex events, subclass of perdurant. In CIDOC-CRM, crm:E2_Temporal_Entity and its subclasses are defined as perdurants, including events. Institutional Facts (aaao:ZE1) and its subclasses, including Function Status, are declared as temporal entitities crm:E2, and not specifically as events. Therefore, they do not explicitly comply with the definition of event provided by UFO, on which the storyline model is based. For this reason, more research is needed to fully understand the implications of reusing storylines as a complex object composed of statuses in which the object acquires different functions. This is left for future work.

Whereas historical frames allow for observing objects in situations or storylines in distinct event types based on frequencies in duration, ephemeral events are far more fluid and fuzzier.

This module describes how some characteristics of ephemeral events can be captured (group of requirements R4). It reuses existing models without proposing new classes or properties, as the requirements can be already satisfied by state-of-the-art solutions. This can be done by reusing the class crm:E5_Event and crm:E52_Time-Span in combination with the representation of time according to the Extended Date/Time Format (EDTF) specification, the Time Ontology, and the Getty AAT vocabulary (see Figure 13).

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Figure 13.

Module to express the characteristics of ephemeral events by reusing existing ontologies. Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

In CIDOC-CRM, the class E5_Event represents “defined and coherent processes and interactions of a material nature, in cultural, social, or physical systems,” in which the constituents “contribute to an overall effect.” However, they are not required to produce permanent changes to the objects in question. Some examples given in the documentation are statements made during meetings and performances. As E5_Events may or may not influence the properties of participants and can be specified with fuzzy time intervals, they are feasible to represent the ephemeral events included in this study. They are intended as 1) events of short duration with no specific beginning or end (e.g., the swinging of the scent thuribles in the procession), 2) events as part of immaterial CH, such as processions and thematic events related to it, which do not survive through time unless they are documented, 3) instant decisions having permanent effects on the CH objects (e.g., the decision to restore the Chest of Distress without the votive heads).

Indeed, the duration of a temporal entity can be expressed through a crm:E52_Time-Span class, representing abstract temporal extents. Although it is supposed to include a start, an end and a duration, the approximation inherent in our knowledge about historical phenomena, which are fuzzy in nature, is acknowledged in the model. Consequently, E52 classes with unknown time specifications are allowed (Bekiari, Bruseker, et al., 2024, p. 86). The relations crm:P79_beginning_is_qualified_by and crm:P80_end_is_qualified_by can be used to express, in the form of a string, the extreme boundaries of the time span. It should be noted that E52_Time-Span does not express a computable time interval itself, but a description of the time extent of an observed phenomenon. Therefore, when information about the start, end, or duration of an event is present, even in a fuzzy format, it can be expressed through reusing the Time Ontology, which defines computable time indications. Through it, the time:Instant defining the start or the end of a period can be represented, and the time:Duration can be related to an E52 instance with a relation of approximation, indicating the maximum (crm:P82_at_some_time_within) and minimum (crm:P81_ongoing_throughout) duration of the interval. In case the exact time is not known or uncertain, the time values can be expressed through the EDTF Specification as implemented in the EDTF Ontology (requirement R4.2). In particular, the qualifiers “?,” “˜,” and “%” are included in the string indicating a date to mean “uncertain” (e.g., “1540?”), “approximate” (e.g., “1540˜”), and “uncertain” or “approximate” (e.g., “1540%”), are particularly useful in the context of the description of uncertainty related to ephemeral events. Furthermore, periods having an unknown beginning or end can be specified through an empty string (e.g. “ ‘1540/”), and periods having an open start or end are represented with two dots (e.g. “ ‘1540/..”). The EDTF ontology is needed as the specification is not compatible with the XSD time format used by the Time Ontology and the standard for RDF data (Shaw, 2022) (see Section 7.4).

As for many ephemeral events, a start or end is not known, qualitative relations between time entities are fundamental to establish the sequence in which they occur (requirement R4.3). As suggested in van den Heuvel and Zamborlini (2021), Allen’s property can be used for this purpose. This is implemented in the Time Ontology. Whereas multiple types of relation within time entities exist, the time:before and time:after properties are reported.

Nevertheless, the general scope of the class E5_Event that includes, for instance, the creation of a poem makes it still difficult to distinguish ephemeral events from other spatiotemporal events (requirement R4.1). Also, as explained in Section 2, the concept of ephemerality is used with respect to objects intentionally created to be temporary in the art history domain (requirement R4.1). For this reason, this paper suggests including a crm:E55_Type combined with the available terms for the description of ephemeral provided by the Getty Art and Architecture Thesaurus (AAT), which includes descriptors for ephemeral art and architecture. Specific types of ephemeral events and experiences, including odors, can be described using the Odeuropa data model. As the model is aligned with CIDOC-CRM, a od:L12_Smell_Emission can fall within the event in which it may take place. The smell generated by the action (od:L11_Smell) can then be further specified with the specific olfactory experience (od:L13) Tables 10 and 11.

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Table 10.

Reused Classes of the Ephemeral Module (Module 4).

Class	Description
crm:E5_Event	see the definition provided in Table 4
crm:E52_Time_Span	See the definition provided in Table 6
crm:E24_Physical_Human-Made_Thing	“This class comprises all persistent physical items of any size that are purposely created by human activity.” (Bekiari, Bruseker, et al., 2024)
crm:E39_Actor	“This class comprises people, either individually or in groups, who have the potential to perform intentional actions of kinds for which someone may be held responsible.” (Bekiari, Bruseker, et al., 2024)
crm:E55_Type	See the definition provided in Table 8
time:TemporalEntity	“A temporal interval or instant.”
time:Interval	“A temporal entity with an extent or duration.”
time:Instant	“A temporal entity with zero extent or duration.”
od:L12_Smell_Emission	“This class comprises events in which a specific smell has been generated, either by human intervention or because of natural phenomena.”
od:L11_Smell	“This class comprises all olfactory stimuli, or smells, considered as unique and un-repeatable, possibly existing in a specific time and place, to not be confused with possible generalisation.”
od:L13_Olfactory_Experience	“This class comprises activities in which an actor (human or animal) is perceiving a smell.”

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Table 11.

Reused Properties of the Ephemeral Module (Module 4).

Property	Domain	Range	Description
crm:P4_has_time- span	crm:E2_Temporal_ Entity	crm:E52_Time-Span	See the definition provided in Table 9
crm:P82_at_some_ time_ within	crm:E52_Time-Span	crm:E61_Time_ Primitive	“This property describes the maximum period of time within which an E52 Time-Span falls.” (Bekiari, Bruseker, et al., 2024)
crm:P81_ongoing_ throughout	crm:E52_Time-Span	crm:E61_Time_ Primitive	“This property associates an instance of E52 Time-Span with an instance of E61 Time Primitive specifying a minimum period of time covered by it.” (Bekiari, Bruseker, et al., 2024)
crm:P79_beginning_ is_qualified_by	crm:E52_Time-Span	crm:E62	“This property associates an instance of E52 Time-Span with a note detailing the scholarly or scientific opinions and justifications about the certainty, precision, sources etc. of its beginning.” (Bekiari, Bruseker, et al., 2024)
crm:P80_end_is_ qualified_by	crm:E52_Time-Span	crm:E62	“This property associates an instance of E52 Time-Span with a note detailing the scholarly or scientific opinions and justifications about the end of this time-span concerning certainty, precision, sources etc.” (Bekiari, Bruseker, et al., 2024)
crm:P11_had_participant	crm:E5_Event	crm:E39_Actor	“This property describes the active or passive participation of instances of E39 Actors in an instance of E5 Event.” (Bekiari, Bruseker, et al., 2024)
crm:P2_has_type	crm:E1_Entity	crm:E55_Type	“This property allows sub typing of CIDOC-CRM entities – a form of specialisation – through the use of a terminological hierarchy, or thesaurus” (Bekiari, Bruseker, et al., 2024)
crm:P10_falls_ within	crm:E92_Spacetime_ Volume	crm:E92_Spacetime_ Volume	“This property associates an instance of E92 Spacetime Volume with another instance of E92 Spacetime Volume that falls within the latter. In other words, all points in the former are also points in the latter” (Bekiari, Bruseker, et al., 2024)
time:before	time:Temporal Entity	time:Temporal Entity	“Gives directionality to time. If a temporal entity T1 is before another temporal entity T2, then the end of T1 is before the beginning of T2.”
time:after	time:Temporal Entity	time:Temporal Entity	“Gives directionality to time. If a temporal entity T1 is after another temporal entity T2, then the beginning of T1 is after the end of T2.”
time:hasEnd	time:Temporal Entity	time:Instant	“End of a temporal entity.”
time:hasBeginning	time:Temporal Entity	time:Instant	“Beginning of a temporal entity.”
edtfo:hasEDTFDate TimeDescription	time:TimeInterval	EDTF datatype	“Value of an interval, expressed using EDTF.”
od:F1_generated	od:L2_Stimulus_ Generation	od:L1_Sensory_ Stimulus	“This property associates an instance of L2 Stimulus Generation with the L1 Sensory Stimulus which was created by the event.”
od:F2_perceived	od:L3_Sensory_ Experience	od:L1_Sensory_ Stimulus	“This property associates an instance of L3 Sensory Experience with the L1 Sensory Stimulus which was experienced.”
od:F6_evoked	od:L3_Sensory_ Experience		“This property associates an instance of L3 Sensory Experience with a (material or conceptual) entity which is evoked during the experience itself. This includes memories of people or situations, comparison to similar stimuli, references, etc.”

9.1. Interactions Between Tangible and Intangible Cultural Heritage in Regular Recurrent Events of Long Duration and Ephemeral Events

Historical frames. A :HistoricalFrame of long duration, “Culture religious, popular culture of Maastricht 14th C. Today” identifies the essence of the immaterial culture characterized by persisting traits of worship related to the veneration of the saint and the recurrent processions (see module 2 and Figure 14). The culture to which it pertains is represented by the class :Culture, related to the frame through a :refersToCulture property. The class :ObjectInRecurrentRegularEvent represents the series of recurring events “Chest of Distress in pilgrimage procession,” belonging to this culture, as well as the icon:CulturalPhenomenon “devotion for the Chest of Distress.” Nevertheless, smaller parts of the spacetime volume can be identified for closer exploration. For example, the frame identifying the culture in 1962, falling within (crm:P10_falls_within) the previous frame, refers to the slice in spacetime occurring in that year. Both frames are related, respectively, to crm:E52_Time-Span and to the city of Maastricht (crm:E53_Place) through the relations inherited from the superclass crm:E92_Spacetime_Volume, respectively, crm:P160_has_temporal_projection and crm:P161_has_spatial_projection. As the former timespan presents characteristics of indeterminacy, it is further described with EDTF time specifications, as defined in Module 4. To this aim, a time:Interval instance is related to the period from circa 1409, in which the indeterminacy of the date attribution is indicated by a ”˜,” to today, that is, an open period represented by two dots. The relation is established through the property edtfo:hasEDTFDateTimeDescription, which provides a mapping between the EDTF specification and the XSD times expressed by the Time Ontology.

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Figure 14.

Modeling of the regular recurrent event of the Chest of Distress in pilgrimage procession, including the specific event of the 1962 procession (case 1). Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

Recurrent events. Recurrent events can be modeled through the :ObjectInRecurrentRegularEvent class, defined in Section 8.1. This identifies events that are planned to occur regularly in time. The class includes (dul:includesObject) the Chest of Distress and further unifying factors (rss:hasUnifyingFactor), such as the city of Maastricht (crm:E53) and the train of relic holders (crm:E74_Group). Two time intervals during which the procession regularly occurred are represented through time:Interval. These are further described by the EDTF time specification to include the features of an open period (from 1874 to today, represented by two dots) and an uncertainty in the date attribution (“1517”).

Specific events and ephemeral objects. Following the Recurrent Situation Series ODP, the recurrent event class is related to specific events which are making part of it through the relation :hasMemberEvent. In this way, specific aspects of single events can be modeled. An example is the Septennial Pilgrimage Procession of 1962 which had the specific theme: “Proclaiming the Riches of Christ.” The artist Jerôme Goffin designed clothing and temporary, ephemeral structures and installations for this single event.

The traits can be modeled with CIDOC, indicating that the E12_Production of every object made use of the design (crm:P33_used_specific_technique, crm:E29_Design_or_Procedure) created by Jerôme Goffin (crm:E65_Creation, related to the author and the timespan). A drawing depicts (crm:P62_depicts) the thematic design. The property crm:P129_is_about relates the design to the theme, represented by an instance of crm:E89_Propositional_Object.

The objects, which have an ephemeral nature, as they are intended to be used only for that occasion, are specified as ephemeral through the relation crm:P2_has_type, identifying the AAT term “temporary buildings” and “ephemeral.”

The event identifying the procession consists of (crm:P9) a more specific activity, namely the swinging of thuribles, which create the olfactory experience of the scent of incense, modeled through the Odeuropa ontology (Lisena et al., 2022).

In the popular culture of Maastricht, there are cultural practices that do not recur regularly over time, but have a specific meaning and function. The Chest of Distress is brought out and carried through the streets of Maastricht to protect its inhabitants in times of danger. Although a regular interval cannot be defined, the act acquires a particular function and meaning, based on defined unifying characteristics at these occasions. In this section, the irregular recurrent event of the Chest brought out of the basilica on these occasions is represented (see Figure 15). The observed object, that is, the Chest, is related to the :ObjectInRecurrentIrregularEvent class, which represents the collection of events presenting the same characteristics. The property :includesFact relates the object to the function status it has in the recurrent events (in this case the function of protection by the Chest when brought in procession). The relation :includesEventsOfType declares the constant type that these events in the pattern have (e.g., a public procession). As the Object in Recurrent Event class is a subclass of dul:Situation, the pre-knowledge reference Frame (see Section 4.1) allows the identification of the function of the Chest to be expressed through a dul:Description.

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Figure 15.

Modeling of the recurrent irregular events of procession of the Chest of Distress in cases of emergency (case 2) and the ceremony of drinking from St. Servatius’s vessel as a healing practice (case 5). Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

Similarly to the previous example, the :ObjectInRecurrentIrregularEvent is related to the :HistoricalFrame to which it refers and to a time interval whose uncertain boundaries are described with the EDTF specification.

During the restoration in 1962, many decisions were taken that modified the function and iconographical meaning of the Chest of Distress (see Section 5). Among them, the votives added in 1450 ca., expressing the strong popular devotion for the Chest of Distress, were removed. In addition, the glass stones, symbolizing eternal salvation, were removed and replaced with precious stones with esthetic functions. These events contributed to the change of the function of the Chest from a devotional to a more esthetic one, although the role of protection remained present in the processions. In this section, the focus is on modeling the removal of motives and the addition of gemstones as part of the actions that resulted in a change in function (see Figure 16).

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Figure 16.

Modeling of the change of function of the Chest of Distress from a devotional to an esthetic one due to changes made during the restoration process (case 3). Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

Events that result in physical changes of the object. In the described example, physical changes of adding or removing parts of the Chest led to a change in the object’s function, without affecting its identity (i.e., the object remained identifiable as the “Chest of Distress”). For this reason, the chest is modeled as a unique instance of crm:E22. CIDOC-CRM classes are used to describe the actions of addition and removal of physical parts (respectively, crm:E80_Part_Removal and crm:E79_Part_Addition) that relate the chest to the added or removed parts (crm:P113_removed; crm:P111_added), respectively, the votive heads and the gemstones. The actions diminish (crm:P112_diminished) or augment (crm:P110_augmented) the object. Both actions have the same time indication (crm:E52) of 1962, the year in which the restoration took place. As both actions have crm:E7_Activity as superclass, it can be indicated that they were carried out by the group of experts and restorers that was responsible for the restoration (crm:P14_carried_out_by the crm:E74_Group). Another instance of crm:E79 is used to indicate the addition of the votive heads performed in 1450 ca.

Function of the object and its changes over time. In this case, the specific parts of the object added or removed were characterized by the overall function of the chest. For this reason, two classes identifying the votive (:SocialFunction) and the esthetic functions (:PracticalFunction), are respectively related to the votives (crm:E22) and the gemstones (crm:E22) through the relation :hasFunction. As illustrated above, the evolution module 8.3 can be applied in this case study to express that the physical interventions initiated (aaao:ZP111) a new function status (aaao:ZE5). It identifies the prominent esthetic function of the Chest, which comes after (aaao:ZP113_has_successor_status) a previous status, which represents the social-religious devotional function that the object had before the restoration. In this way, a relation between the material changes of the object and the contextual activities that cause them is registered.

Historical Frames. To indicate to which cultural context the actions belong, four historical frames are specified. The first one identifies the religious and popular culture of Maastricht from the 14th century to today. It is characterized by an icon:CulturalPhenomenon, in this case, the devotion to the Chest of Distress. A smaller frame, part of it (crm:P10_falls_within) indicates the state of affairs present in 1450 ca., which is the context of the addition of the votives. Another frame, which overlaps with the first one (crm:P132_spatiotemporally_overlaps_with), indicates the belief system of the group of experts that guided the restoration in the years 1958-1962. It includes the icon:CulturalValue of values such as the esthetic features of the CH artifacts. Such a frame could be seen, for instance, as a slice of a fourth frame of Western restoration practices applied in the twentieth century.

Storyline. A ga:ObjectStoryline of the Chest of Distress collects all the events in which it participates (crm:P12i_was_present_at). Being perdurants, physical restoration interventions of part addition and removal can be added to the storyline. Nevertheless, for the problems of aligning a temporal entity as defined in CIDOC-CRM with the Storyline model, already discussed in Section 8.3, we do not include the instances of aaao:ZE5_Function_Status in ga:ObjectStoryline.

The event of the restoration of 1962, illustrated above, brought significant changes in the iconography and iconological meaning of the Chest. One of the most relevant variations concerns the scene on the short gable representing St. Servatius between angels. As described in Section 5.1, originally one of the angels was giving the bishop’s staff to St. Servatius. This action was crucial in legitimizing the role of bishop acquired by the saint. It implied that this role was given to Servatius by God himself, via the intervention of the angel. As a consequence, the removal of the staff had a considerable impact on the symbolic message that it expressed.

In Figure 17, the specific scene in the gable on the short side is modeled as a feature (crm:E26_Feature) of the Chest. Similarly to the third case of interaction, the physical removal of the bishop’s staff from the scene can be described as a crm:E80_Part_Removal performed by the group of experts and the restorer in 1962. It has as context the frame of restoration practices in the years 1958-1962. In this example, the physical interventions caused a variation on the conceptual level of the object. Therefore, crm:E80_Part_Removal motivates (crm:P17i) a :ConceptualVariation instance, occurred in 1962, which :conceptuallyModifies and :creates ConceptualVersion two versions of the immaterial visual part of the item (crm:E36), related to the feature through the property crm:P65_shows_visual_item.

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Figure 17.

Modeling of the change of iconographical meaning of the scene representing St. Servatius as a bishop as a consequence of the restoration performed in 1962 (case 4). Created by Sofia Baroncini. Available at Zenodo (DOI: 10.5281/zenodo.20393679). Licensed under CC BY 4.0.

The relation dul:precedes indicates that the first one occurs in time before the second. Classes of the ICON ontology can signify the subjects and meanings represented in the CH object (crm:E36) before and after restoration. The previous CH object version depicts, at the second level of interpretation (icon:iconographicallyDepicts), the subjects of the bishop staff (icon:NamedObject), the angles and the saint (icon:Character), the action of the angel giving it to St. Servatius (icon:Event), and the symbolic reading of the gesture as God giving to St. Servatius the role of bishop (icon:Symbol). At the third level of interpretation (icon:iconologicallyRepresents) the icon:Belief that St. Servatius became a bishop by the will of God is acknowledged. This is in turn related to the :HistoricalFrame of the culture of Maastricht. The loss of meaning is expressed by the fact that only the figures of St. Servatius and the angels are represented in the instance of the CH object after its restoration.

Both the immaterial (crm:E36) and material (crm:E22; crm:E26) parts of the CH object can be included in a Storyline. As the object is examined in its components, they participate in a ga:ComplexObjectStoryline.

The last case of interaction presented here is the acquisition of meaning and function through the healing ritual of drinking from the St. Servatius cup illustrated in Section 5.

According to the belief (the event is not considered to be historical from a non-Catholic perspective due to inconsistencies in historical sources), St. Servatius drank from a cup, which was identified as the 1st-century AD Roman vessel discussed here. Hence, the Roman vessel, which originally had a sole practical function, obtained a new healing function in the religious context from the 14^th century onward. This meaning comes into being when believers drink from it, usually during an intimate ceremony. In this case, a believed fact had a long-lasting impact on the cup’s function in the upcoming centuries. One of the many occasions in which the drinking ceremony took place was during the Spanish flu of 1918 (Figure 15).

Such a recurring situation can be represented through an :ObjectInRecurrentIrregularEvent class, having as members the events in which it took place, for example, the E5 Event of the ceremony that happened in 1918. This situation includes events that have as a type “an informal ceremony of drinking from the vessel,” which defines the characteristics of the events involved. Whereas the recurrent event is related to the :HistoricalFrame of the religious, popular culture of Maastricht from the 14th century to today, the 1918 event is related to the Historical Frame of that specific year.

Furthermore, an instance of aaao:ZE5_Function_Status relates the same object (namely, the vessel) with the drinking function (:PracticalFunction) it had in the Roman context. This is represented in another :HistoricalFrame instance, through the :hasCreationContext relation. It refers to the Roman context in which the object was created. The fact that the same object is related to two different statuses, in turn associated with two historical frames having different spacetime coordinates, expresses the change of the vessel’s function in the two different contexts.

This modeling allows for relating a function to specific groups of events while identifying relevant cultural traits through the Historical Frame class. Indeed, the historical frame in which the recurrent event is situated includes the belief that St. Servatius drank from that cup. It is modeled as a belief, related to the believed thing through the newly added :believedThing relation (See module 8.2). A further relation :motivates marks the strong influence that the belief had on the practice, relating the Belief to the Object in the recurrent irregular event situation. As the believed event is not considered to be a fact that took place, it is modeled as a Propositional Object (crm:E89). Nevertheless, this choice hinders the possibility of expressing the change of function through the property class aaao:ZP111_initiated, which necessarily requires an event causing the shift from one function status to another.

10.1. Conclusions

This paper explored, based on a theoretical-historiographical overview of the concepts of frame and historical time, the creation of a system of historical frames to analyze, interpret, and annotate interactions between material and immaterial expressions of the arts in their cultural contexts. A concrete outline of a historical frame model based on evidence-based storylines was presented as a step toward solving the complex Historical Framing Problem. Modules were proposed to describe the various functions, cultural traits, ephemeral events, and the material and immaterial evolution of the object. A historical frame as part of this system was modeled in more detail to demonstrate how it could be used to capture spatiotemporal views, in particular of ephemeral events in interactions between tangible and intangible CH. Based on this historical frame model and tested against five types of such interactions in a case study of changing functions and iconographies of material objects in the cult of St. Servatius, four ontological modules were developed. These modules: 1 Object in Situation, 2 Historical Frame, 3 Evolution, and 4 Ephemeral in Tangible and Intangible Cultural Heritage, integrated existing ontological solutions based on CIDOC-CRM and/or DOLCE. Extensions were proposed to model different (ir)regular recurrent, unique, and ephemeral events, their functions, their relations with immaterial culture, and their evolution over the timespace volume.

10.2. Discussion

The proposed ontological modules have been tested through the descriptions of five cases of interaction between tangible and intangible CH present in the rich example of the St. Servatius’ Chest of Distress.

10.3. Future Work

Four modules were created through the combination and extension of standards (CIDOC-CRM and DOLCE) with classes of AAAo, ICON, the Time Ontology, Storylines, the EDTF Ontology, and Odeuropa to represent relevant aspects of the interactions between tangible and intangible CH. Common alignments have not yet been incorporated to avoid potential inconsistencies between the ontologies used. Alternatively, classes aligned with different ontologies are related in the model through properties. The proposed ontological framework can be further integrated with recently released ontologies that address the representation of social facts, such as the Semantic Data for Humanities and Social Sciences (SDHSS), an extension of CIDOC, which is also based on DOLCE. This may integrate our model with more detailed information on the societal traits considered to be relevant in the framed context(s). Furthermore, we envision conducting research to realize a new model of storylines that includes 1) spacetime unity and 2) socio-cultural characteristics.

Interactions between objects of tangible and intangible CH were presented as storylines that often could be well defined in spacetime, but in other cases, such as in ephemeral events, were fuzzy. This implies that in the storylines, elements of uncertainty are introduced. With the aim in mind to use historical frames to analyze and present evidence-based histories, further research is foreseen. This research is intended to establish how the historical frame system can be connected to ontological models of uncertainty. These models must be able to deal with various types of uncertainty, such as in vagueness ontologies (Alexopoulos et al., 2014; Ghorbel et al., 2019), but also with the different phases in which uncertainty can occur.

Although the problem of uncertainty in the temporal modeling of interactions between tangible and intangible CH cannot be solved immediately, further research and modeling is foreseen in the short term. ²⁷ Future work includes furthermore additional alignments with existing ontologies and extensions of tangible and intangible CH interactions models based on more interdisciplinary case studies (e.g., material culture, anthropology, social sciences).