Towards an Ontology for Historical Persons
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Given at "Culturecloud, Co-reference, Archive workshop" 4 June, 2013, National Archives, Stockholm.
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Towards an Ontology for Historical Persons
- 1. Towards an Ontology for Historical Persons John Bradley Department of Digital Humanities King’s College London john.bradley@kcl.ac.uk
- 2. Tim Berners-Lee on Linked Data All kinds of conceptual things, they have names now that start with HTTP. I get important information back. I will get back some data in a standard format which is kind of useful data that somebody might like to know about that thing, about that event. I get back that information it's not just got somebody's height and weight and when they were born, it's got relationships. And when it has relationships, whenever it expresses a relationship then the other thing that it's related to is given one of those names that starts with HTTP. Tim Berners-Lee: Linked Data presentation at TED 2009 2
- 3. Linked Data and History If linked data is to connect historical data, it is likely to work best when centered on three kinds of entities: Sources Places People 3
- 4. Prosopography as Linked Data “A particular prosopography aims to amass and present clearly a quantity of information on all individuals in a given category” (PASE website) Prosopography has traditionally been a linked data-like exercise 4 SourcesPeople From J.R. Martindale, The Prosopography of the Later Roman Empire, 3: A.D. 527-641. Cambridge: Cambridge University Press. 1992. Places
- 5. Digital Prosopographies on the WWW: as the main project and “on the side” 5
- 6. Person Identity: URIs URIs provide an excellent model for identifying persons globally PBW “URI”: http://db.pbw.kcl.ac.uk/pbw2011/entity/person/143353 6
- 7. Same person: multiple URIs Linked Data/Semantic Web can even accommodate separate URIs for the same person: 7 owl:sameAs owl:sameAs owl:sameAs http://www.pone.ac.uk/record/person/12/http://db.poms.ac.uk/record/person/2046 http://www.oxforddnb.com/view/article/22966
- 8. Prosopography: more than “just” person identification Historical persons survive for us through their appearance in sources, and historians identify them not only by their name, but also by what they did and by other ways that they are described. 8
- 9. Prosopography and the linked Data Principles 1. Use URIs as names for things 2. Use HTTP URIs so that people can look up those names. 3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL) 4. Include links to other URIs. so that they can discover more things. (Berners-Lee 2006: http://www.w3.org/DesignIssues/LinkedData.html 9
- 10. From “Closed” to “Open” Prosopography Closed: single research team, contained domain, controlled semantics, tight boundary Open: collaboration between partners, fuzzy boundaries, multiple overlapping interests Examples: POMS and PONE PASE to “PASEN” PBW to “Crusades” 10
- 11. PASE->”PASEN”: the move from closed to open data 11 PASE Anglo- Saxons Anglo- Normans Normans 1 Anglo- Normans Other people Anglo- Normans Other people Normans 2 Normans 3 Anglo- Normans Other people The linking of people is only a part of the issue: The linking of data about the people each project holds also needs to be thought about Boundaries between projects not necessarily so clear-cut
- 12. Existing data models for prosopography 12 DDH: “factoid Model” PBE/PBW PASE POMS PONE Charlemagne DDH: Clergy DB Model FOAF
- 13. OHP and other models 13 DDH: “factoid Model” DDH: Clergy DB Model Ontology for Historical Persons FOAF Inference Layer
- 14. FOAF: Friend of a Friend “FOAF is a project devoted to linking people and information using the Web. Regardless of whether information is in people's heads, in physical or digital documents, or in the form of factual data, it can be linked.” “FOAF does not compete with socially-oriented Web sites; rather it provides an approach in which different sites can tell different parts of the larger story, and by which users can retain some control over their information in a non-proprietary format.” 14 http://xmlns.com/foaf/spec/
- 15. OntoLife: Personal knowledge management “model life by describing a person’s Characteristics Relationships Experiences” 15 Kargioti, Eleni (2009). OntoLife: An Ontology for Semantically Managing Personal Information
- 16. TEI: Names, Dates, People and Places “... this module allows one further to represent a personal name, to represent the person being named, and to represent the canonical name being used. A similar range is provided for names of places and organizations. The main intended applications for this module are in biographical, historical, or geographical data systems such as gazetteers and biographical databases, where these are to be integrated with encoded texts.” TEI, section 13 introduction(http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ND.html) 16
- 17. TEI: Personography: “Basic Principles” Information about people, places, and organizations, of whatever type, essentially comprises a series of statements or assertions relating to: characteristics or traits which do not, by and large, change over time characteristics or states which hold true only at a specific time events or incidents which may lead to a change of state or, less frequently, trait. • TEI, section 13.3.1 (http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ND.html) 17
- 18. TEI: Personography textual markup: Marriage of William Morris Persons identified by <person> tag References to people in text tagged with <name> An event tagged in the text with <event> No roles for people in event specified 18TEI, section 13.3.2.2 (http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ND.html)
- 19. Core structure for DDH’s Prosopographical databases PersonPerson AssertionAssertion Authority ListsAuthority Lists Assertion TypeAssertion Type SourceSource LocationLocation PossessionPossession 19 Instance of Typed by Connected to Connected to Appears in Connected to RoleRole DateDate
- 20. Structuring Prosopography: the factoid Pasin, Bradley (2011). Factoid- based Prosopography and Computer Ontologies: towards an integrated approach 20
- 21. Source Assertion: A Document Interpretation Act 21 Pasin, Bradley (2011). Factoid- based Prosopography and Computer Ontologies: towards an integrated approach Martindale asserts that... “Greg. Tur HF” asserts that... Victorius 4 imprisoned Eucherius 4 “Two levels” of assertion
- 22. CIDOC-CRM: its place in an OHP? 22
- 23. Place Ontology Place Source Ontology (FRBRoo?) Source Person Assertion Role Event Trait/State Relationship Office/Title/Occup Dates Event Type Group Name Possession A Prosopography Project AL: Offices, etc AL: Event types OHC Persons Assertions A Source Repository Sources A Place Repository: e.g. Pleiades Places
- 24. Building the OHP Needs to be a collaborative venture I have begun to talk up the idea If there is interest, a workshop to explore it and develop ideas could be set up at King’s in London. Comments?? 24
- 25. 25
Notes de l'éditeur
- We at the Department of Digital Humanities – DDH – at King’s College London have worked on digital prosopography for years now – my second substantial DH project when I joined then CCH in 1997 was the Prosopography of the Byzantine World. Since then, I and my department have been involved in the development of 5 other prosopographical projects: for Anglo-Saxon England, for the Clergy of the Church of England, two for northern Britain, one for Charlemagne’s Europe. As you will hear, based on this experience, I believe that prosopographical thinking has something specific to offer to the world of linked data. In my talk today I am outlining, for the first time publically, some thoughts about what I&apos;d like to turn into some kind of the project: the development of an Ontology for Historical Persons.
- It seems to me that Linked Data has developed out of the Semantic Web as a kind of simplification of its goals. Here is a quote from a talk Tim Berners-Lee gave at the TED 2009 conference about Linked Data which outlines the key ideas behind Linked Data: that one names things (not only web pages) by giving them URIs (like URLs) that start with http. that if you give one of these to the WWW, you get back useful information in a standard format (elsewhere, the format is specified to be the structured-data oriented RDF format) and, that the data you get is situated in a digital world that is linked to other pieces of data
- I am a digital humanist and it is natural, then, for me to think of Linked Data in the context of the humanities. In the context of digital history, linked data has the potential of enabling a much richer use of digital historical data created by historians around the globe, and it could create a new digital global eco-system for carrying out historical research. One would expect that historians will be interested in approaching this – still imagined – web of linked data historical resources primarily from three different starting points: Historians are likely to turn to the web – indeed, already do so when they can, to locate and access good quality textual sources. The preparation of texts for scholarly use is a highly specialised activity and one can expect there to be centres of expertise all around the world that would focus on the scholarly task of preparing and publishing editions of the sources. One can well imagine URIs being assigned to digital sources that operate as identifiers as a matter of course. Information about place is also important to historians, and often provides a bridge to the interests of the general public. Here too, specialist knowledge is necessary to prepare and organise data about historic places. The sorting and management of historical places is already happening. The Pleiades project (http:pleiades.stoa.org) provides us with an excellent example of how to structure and make available information about historic places. Their website tells us that they have close to 100,000 places, names and locations in their database, and that it provides &quot;extensive coverage for the Greek and Roman World&quot;. The third perhaps most obvious &quot;entry point&quot; to historical data would be via persons. And here we come to a linked-data perspective on prosopography – what I’m talking about here.
- This, rather informal definition provided by our Prosopography of Anglo-Saxon England -- PASE – captures the essence of a prosopographical project. It says that prosopography is a kind of historical study that &quot;aims to amass and present clearly a quantity of information on all individuals – people – in a given category&quot;: for PASE this was Anglo-Saxon England. To build PASE, its researchers read a substantial number of Anglo-Saxon sources, more than 2700, ranging in size from a short legal charter, up to the Anglo-Saxon Chronicles and the 1086 – post Norman conquest – Domesday book. They worked to identify all the people named in these various sources, and recorded information about them in a database. Each name in the source thus turned into a reference to a person, and PASE becomes a prosopography: aiming to provide a definitive list of people that appear across all the surviving Anglo-Saxon sources. Even before prosopography became a digital activity as it was for PASE, it is worth noting for a moment that it has always been in some sense a linked data kind of activity. Here is an entry for a person – Eucherius 4 – who appears in John Martindale&apos;s Prosopography of the Later Roman Empire, volume 3 – a prosopography that appears in print, and dates from 1982. As is the case in all the other entries about people that Martindale has identified, a person is given a standardised name (arguably like Linked Data&apos;s first URI requirement), information is provided about him when one looks him up (the second requirement), and the information is richly linked between sources, to places and other people (the 3rd requirement). Here we see, then, exactly the three key &quot;historical entry points&quot; I mentioned in the last slide: historical sources, people, and places.
- Prosopography, as a project that aims to identify historical persons, is widely done as a kind of primary goal in the digital humanities: I show here the web pages for several of &quot;our&quot; projects: The Prosopography of the Byzantine World, the Clergy of the Church of England Database, as well as PASE (already mentioned). I couple “our” projects with a few of other mainly prosopographical projects that I know about: the Prosop project of Will Hanley (Florida State University) which aims to create &quot;a large database of historical names&quot; which will hold data contributed by others, Caroline Bawden&apos;s &quot;Who were the Nuns&quot; project which aims to &quot;identify those [Catholic] women who entered the English convents from the foundation of the first new house in Brussels in 1598 until the end of the exile period (in England)&quot;, Alison Booth&apos;s &quot;Collective Biographies of Women&quot; which is creating what she describes as “an annotated bibliography of English-language books that collect three or more short biographies of women only: a forgotten British and American publishing tradition that provided a surprisingly ample and wide-ranging biographical history of women&quot;, and the Orlando project which &quot;is an online cultural history generated from the lives and works of over 1200 [British woman] writers&quot;. Note the temporal and cultural overlap between, say, Orlando and CBW: an issue I shall return to shortly. Other projects, although not perhaps primarily prosopographical, take on some degree of prosopography “on the side”. The public website that gives access to the Merlin database at the British Museum, for example, links and identifies people associated with the objects it describes. Indeed, I have included a simple illustration of people in a CIDOC-CRM structure – the same one Martin Doer showed us yesterday – because the CRM, although aimed at organizing data about cultural objects, clearly identifies people associated with these cultural objects as a part of the cataloguing process. There must be thousands of projects which publish their results on the WWW that have an historical prosopographical focus, or at least an historical prosopography component.
- Prosopography aims to uniquely identify a person, and when the prosopography is structured and digital, this unique identification maps naturally into a URI. Indeed, as a result, as we have been revising our web presence for our prosopographies we have been turning these unique identifiers we already have for people into direct RESTful links directly to the data that the project holds about the associated person, thus allowing these links to act as URIs that identify that person. Here we see the RESTful URI to our Byzantine World project that links to, and therefore identifies, one particular PBW person: a certain Kallinikos who has a hegoumenos at Athos.
- The &quot;AAA&quot; principle described by Allemang and Hendler in their book &quot;Semantic Web for the Working Ontologist&quot;: that in the WWW anyone can say anything about any item, is extended by them to recognise that the existence of a global URI to identify a person doesn&apos;t necessary mean that there is only one global URI for that person: in the WWW different project can legitimately define their different URIs for the same person. Here we see three different URI references for the same person Roger de Quincy, and two of these IDs for de Quincy – in the People of Medieval Scotland and People of Northern England databases – are from scholarly related projects. Indeed, there is a formal linking mechanism is in their separate databases precisely so that the project teams can assert when entries in the separate projects refer to the same person. Also, one of the projects provides a mechanism to link to the online Dictionary of National Biography. I have identified these formal links as a kind of &quot;owl sameAs&quot; connection.
- Although the identification of persons is, obviously, a key part of what prosopography is about, and hence, as linked data, the assignment of URIs for people is an obvious part of digital prosopography (indeed, its first principle), we need to think about the other parts of the linked data principles as well. The 2nd principle: that when one uses the URI to fetch something from the WWW that useful data comes back: is also a key idea of prosopography. Since the only information we have about historical people comes from how they are presented in the historical record, the collection of information we have about them that has been gleaned from those records is arguably a key part of their actual historical identity. At present, in our projects at least, invoking the URI to get the data from our structured prosopographies only delivers a web page that presents the data for a human reader through a browser – however, the structured nature of the data behind these dynamically created web pages is entirely compatible with the ways of thinking about data that is present in linked data’s RDF – indeed, we have been recently exploring how to best map our PASE data into RDF structures. Thus, from a linked data perspective, where the data is presented as RDF and assumed, at least, to be highly structured, the formal nature of this data is therefore both technically and historically as tightly connected to the identity of the person him- or her-self as the URI is.
- Our thinking about prosopography for linked data needs minimally to accommodate all four of Berners-Lee&apos;s linked data principles. However, these principles, by themselves, only deal with a part of the problem that arises if one thinks about historical structured data linked together but created by semi-independent projects around the world. Indeed, I believe that once one recognises that different teams of people can say different things about the same historical person (Allemang and Hendler’s AAA principle again: “anyone can say anything about any topic”) one has to go beyond these 4 basic linked data principles to bring in some of the other ideas that come out of that other major component of the semantic web: computer ontologies. Perhaps the Web, with its ready access to material from all over the world already makes us more aware that separately conceived projects would be most useful if somehow the data they contain could fit together. This is most definitely an issue that is brought into sharp focus with prosopography. A single individual can appear in more than one historical context where he or she could well be represented quite differently. We might expect this phenomenon to occur with prominent people such as Alexander the Great, but who would have thought that a less well known person such as Harold Harthrada – in our Anglo-Saxon project – also makes an appearance in Byzantium where our PBW project operates?
- Furthermore, this AAA phenomenon is beginning to transform even how projects, conceived as connected as a single research umbrella are beginning to operate. I characterise here how over the past few years what has been happening. The important thing is that our various projects that in the past would often be characterised by being conceived as coming about from the labours of a single research team have begun to shift to a much more open, multi-player collaborative context. Whereas these older projects often worked hard to define a closely defined boundary – a prosopography of the Anglo-Saxons, or the English clergy, and worked hard to define a suitable, but largely self contained, conceptual framework in which to operate; our partners have begun more recently to talk in terms of much larger research ventures characterised by teams of more independent researchers, often with fuzzy boundaries between their interests, but with research interests which, although they might connect together in some ways, also represented different and even not-fully-compatible viewpoints. Three brief examples (expanded in presentation...)
- A second example: The move from PASE to what I call here “PASEN” is even more striking. PASE – our Anglo-Saxon prosopography, ends more or less with the creation of William the Conqueror’s Domesday book. It provides information about Anglo-Saxons both before the Norman conquest in 1066 and also after it in 1086, but also contains a rich set of data about the Anglo-Normans who gradually took over all elite positions in the English Kingdom. Domesday book provides, then, a kind of transitional document between an Anglo-Saxon-oriented project that has been PASE and that covers about AD 600 to about 1086, to an Anglo-Norman period that begins with the Norman conquest in 1066. PASE&apos;s Domesday historian Dr Stephen Baxter is a good example of somewhat who has become caught up in this transition. On one hand, he has continued to work with some of the thorny issues that arise out of the identification of Anglo-Saxons in Domesday book. However, he has more recently begun to develop a new research agenda taking up the history of the Normans. Clearly, work on the Normans takes us outside of England and Anglo-Saxon Scholars to areas of France and even other areas in Europe where the Normans were important and that involve different, Norman studies, scholars. Indeed, any Norman individual can only partly be understood by considering his or her role in the post-conquest England, and many can only partially be understood by focusing on their activities in continental Europe. Furthermore, there are already well established centres for scholarship for the Normans in France and elsewhere that focus on their historical role in other places outside of England. The project becomes, by its very nature, a much more collaborative, and diverse, one. Thus, although Stephen and I originally jokingly referred to the extension of PASE to include more about the Normans in England to require the change in name of the project from PASE – Prosopography of Anglo-Saxon England – to PASEN – Prosopography of Anglo-Saxon England and the Normans&quot;; in reality the story of future work (and the conception currently being worked on in project proposals) would need to recognise a much more open, collaborative venture than PASE needed – bringing in experts with a focus outside of England with those who focus on the Anglo-Normans. From a linked data point of view, PASE would become one partner among several Norman-oriented projects. Entity domains will overlap between projects not only regarding people, but also overlapping for sources and places; each project could have their separate but linked list of Normans active in their area, each one with different non-Norman people also involved, and – importantly for my discussion today – each with a different sense of the kinds of data they were collecting about their people.
- The question of different project data organised according to different structures is one that must confront any project that aims to bring material together from different projects, such as this imagined Norman of crusades project. Although our Norman project discussions are not far enough advanced so that we know what data is being collected by the different collaborators, we already do know that different prosopographical projects use different data models upon which to base their data structures. Are there common concepts that operate arguably across prosopography that help? We ourselves at DDH have been involved in a number of digital structured prosopographies that cover a broad range of cultures and time periods, and most of them use data models that are based on our so-called &quot;factoid&quot; model, which I will introduce briefly in a couple of moments. However, not everyone doing prosopography can be expected to use our factoid model: indeed, even our very own Clergy of the Church of England project does not use the factoid model directly. Indeed, a look around at other projects outside of our collection of prosopographies shows the range of data models that have been applied. See, for example, the Digital Prosopography of Renaissance Musicians, who based their model for data about their musicians around FOAF with some extensions. The Orlando project uses an XML tagging system for their biographical documents that is only loosely connected to the well known TEI markup scheme, and was developed specifically to deal with the kind of events that they found to appear in the lives of the women authors they were working with. Ralph Mathisen, in his 2007 article in Katherine Keats-Rowan&apos;s collection &quot;Guide to the Principles and Practice of Prosopography&quot; shows us the input screen for the Attica Website, and therefore reveals the relatively simple structure behind that prosopography. Then, we have OntoLife: an ontology that is focused on the assembling of data for what it calls &quot;Personal Knowledge Management&quot;, and has been seemingly created for representing information about a modern-day professional individual: with attributes for information like Medical history, Work Experience, Language Skills, place of birth., etc. Finally, again we see CIDOC-CRM with its structure for Actors and events in which they took part. Anyone applying its model to historical figures must be doing prosopography to some degree. It is striking that if we were able to pull RDF data directly from the differing structures behind each of these projects (Linked Data’s 3rd principle) they would be likely dealing seemingly with common semantic entities: persons, places, activities, etc – but their detailed structure would not be immediately compatible. Can anything be done about this?
- Perhaps we can begin to see the need for a common conceptual framework which allows us to associate these different kinds of data. Like the CIDOC-CRM which provides a common framework for information about cultural artefacts, an Ontology for Historical Persons would provide a common conceptual framework for data about historical persons. In the same way that at least much of the data from any particular cultural artefact management system could then be mapped to the common concepts of the CIDOC-CRM because the CRM represents a broadly-agreed understanding of the semantics of data held by cultural institutions about their collections, perhaps the data from these different prosopographical projects could also be mapped to the common concepts of an OHP. We can perhaps see two questions immediately: Is there a common conceptual framework that applies across prosopographies? And Is there already an ontology in existence that deals with this framework? There are, of course, already a number of ontology, or ontology-like models that inhabit a domain space that is similar to the one the OHP would work with. Will any of these already do?
- Perhaps the most obvious semantic web prosopography ontology is FOAF: Friend of a Friend. Although FOAF really has a modern social web domain, with attributes for person related to what any thoroughly modern digital citizen would want, it is nonetheless occasionally used as the basis for modelling historical and semi-historical persons too – remember the &quot;Digital Prosopography for Renaissance Musicans&quot; I mentioned earlier, for example. To me, too many of FOAF’s attributes reflect assumptions about modern life in the digital and internet world. With FOAF being used so widely in spite of this, however, I would hope that wherever possible, any similar OHP entities would be explicitly related to FOAF properties and classes through subclassing or equivalence.
- OntoLife – an ontology for representing &quot;personal information&quot; has a broader domain included than FOAF, but still seems to have a focus on a modern perspective on a person&apos;s life. A history project that involved telephone numbers, say, or identity cards, or skills and qualifications, is likely to be a 20th century one, and might also one that, like FOAF, is likely to focus on people in their professional life. OntoLife might be useful here. However, as much as I liked the overall categorization of the kinds of information organised within the OntoLife ontology as representing a person&apos;s &quot;characteristics, relationships [to others as individuals, and to organisations], and experiences&quot;, OntoLife feels like a rather inadequate basis for an ontology meant to deal with a broad range of historical periods. However, although OntoLife doesn&apos;t seem to be an appropriate model to form the basis for the OHP, one would want to allow compatible concepts to be mapped to it – in the same kind of way that any OHP would need to be able to map appropriate ideas to FOAF too.
- Having looked at two prosopographical-like models that did not emerge from the humanities, we should turn briefly to consider the greatest structured data initiative in the Digital Humanities: the Text Encoding Initiative – or TEI – because like many fields in the digital humanities, it has something to offer here! What does it have to say about digital Prosopography? Although TEI primarily focuses on the issues in marking up texts for textual scholarship, it does also venture into the representation of non-textual items. The TEI&apos;s chapter entitled Names, Dates, People and Places brings a stronger historian’s perspective to the representation of material about historical person than FOAF or OntoLife. Although the chapter starts off very usefully focusing on the relationship between names and people – definitely a part of the task of a prosopographer (although only a part of it, as I hope earlier parts of this presentation has made clear), section 13.3.3 is entitled &quot;Biographical and Prosopographical Data&quot;, and in its introduction it says that it is aimed at researchers &quot;creating or converting an existing set of biographical records, for example of the type found in a Dictionary of National Biography&quot;, or creat[ing] ... a database-like collection of information about a group of people, possibly but not necessarily the people referenced in a marked-up collection of documents&quot;.
- The TEI&apos;s biographical and prosopography section begins with a categorization of the kinds of information that this TEI module is meant to support. Its characterisation of the three kinds of information about people connects strongly with our own experience – going back a number of years – in our “DDH prosopographies” for the kind of data that our prosopographers want to work with, and challenges the assumption that I have heard recently that &quot;event-driven&quot; models cover all the needs of prosopography. Traits and states also represent information that historical sources will record about people and many of these do not really map into an event-centered model.
- Later in the guidelines we find an example of the application of TEI&apos;s prosographical module that marks up a bit of text that describes the marriage of the artist William Morris to Jane Burden in 1859. I particularly like the fact that through the use of the event tag TEI provides the recognition that information about historical sources is usually found, and grounded in, textual sources (although it isn&apos;t made clear what the underlying text in this particular example is). There is a clear separation of the person from the name of a person, and we can see here names-as-reference-to-a-person, by being nested inside an event tag, establishing formally the connection of the people named there to the marriage event. The conjunction of source, event, and people that happens in this markup resonates well with our own model for structured prosopography as you will see in a moment. Perhaps the most striking thing missing, however, is that there is no sense of roles for the people being recorded: no one is formally identified as the bride or groom in the structure for example. In sum, there are lots of good ideas that belong in an Ontology for Historical Persons in the TEI guidelines, and because they are in the TEI we can be pretty sure that they will work well with established scholarly text study practice, and are more likely to be recognised as significant by the digital humanities community.
- Now it is time to describe the model for structured prosopography that we have followed at DDH for almost all of our prosographical projects. The &quot;factoid&quot; or &quot;source assertion&quot; model has been used successfully by us in a range of prosopographical projects since the development of the Prosopography of the Byzantine Empire in the 1990s, and although there have been some significant enhancements to the model since it emerged during the creation of PBE, several of its key ideas are still with us. The central idea in it is the &quot;Source Assertion&quot; – formally called the “factoid”. This can be best thought of as an item that represents a spot in a source where something prosopographical happens: where the source makes an assertion about a person or persons that the prosopographer wants to record in his or her data. The assertion might be as simple as giving an historical person a title or naming him or her has holding an office. It might involve more than one person: asserting a relationship between two people, for example that Elizabeth Ist is daughter of Henry VIII. It might represent a more complex thing such as an event in which several people are involved: in the text we have just seen about the marriage of William Morris to Jane Burden more than two people are mentioned has having been involved – and in our source-assertion model, various people involved can be given roles in the event. Any of these assertions can also bring in information about associated geographic places: the event happened at a particular place, or possessions, and, of course, all assertions can have an historical date or range associated with them. The point of the “source assertion” is that it represents a kind of nexus between a segment of an historical source, a group of one or more people, some geographic places and possibly some possessions. Like the TEI personography module, the assertion is not necessarily an event: it could be an assertion that a person simply was bishop or king: what TEI calls a &quot;trait&quot; or &quot;state&quot;.
- We can see factoid/source assertions present even in traditional prosopography. Here we see again Martindale&apos;s article about Eucherius 4 again, and the assertions that he makes, and links to historical sources here labelled up as factoids, or &quot;source assertions&quot;. The final one in Martindale’s short article is shown below it in structured form. We can see the factoid linking two people, with roles attached to them to a spot in a source through its description of a particular relationship and event between them.
- In this article this figure came from Michele Pasin and I looked at elements of the factoid model that mapped onto parts of CIDOC-CRM. Here you see one of the transitional diagrams that eventual lead us to a representation of our factoid approach, in part at least, in terms of CIDOC-CRM&apos;s Classes and Properties. One of the things that came out of this work was the realisation that our model provides two levels of assertion: at one level, in essentially modern times, our prosopographer asserts that a source from historical times says something. The thing the source says is a second layer of assertion that sits in front of the assertion itself. In this diagram, then, we can see that Martindale – our modern-day prosopographer – asserts that Gregory of Tours in his Historia Francorum asserts that Victorius 4 imprisoned Eucherius 4. This &quot;double assertion&quot; construct makes it clear about how our factoid/source assertion model combines the characteristic of being &quot;source driven&quot; with being a prosopographical interpretational act.
- Finally, I’ve already mentioned that CIDOC-CRM has prosopographical components, and that people who use the CRM’s model to represent their collection have the capability to assert things about historical persons. What would CIDOC-CRM offer to a model for Historical Persons too? I can’t say I know for sure! At first glance, perhaps, the CRM would appear to largely model activities that are involved in the collection and management of cultural objects – the kind of work done by archives and museums, rather than historians, and, indeed, many of the classes and properties in the CRM serve exactly that purpose. However, the fact is that the CRM crosses the boundary here and there between cultural objects and historical persons, probably because as I mentioned earlier, museums and archives do; and we can see this in the modelling of images, documents and people involved in the Yalta conference at the end of World War II – all represented in terms of the CRM’s entities. As a result, the CRM has model elements that would play a significant role in an OHP. Its Appellation model, its modelling about existence, and its model of temporal relationships are obvious candidates.
- So, what kinds of things belong in an Ontology for Historical Persons? Here we see a deliberatively rather crude illustration, only partly formal, that touches on the kinds of things that an OHP might deal with. The three ovals at the top would be ontologies, and would hence be primarily be made up of classes and properties. The three boxes at the bottom represent three hypothetical repositories for historical things: of People, of Places, of Sources. The three repositories would likely be maintained by different scholars, and could presumably use the ontologies in the top area of the figure to formally define some of the semantics for their particular pieces of data. Note first, that there are 3 separate ontologies represented here. In the middle, and the largest oval, is our ontology for Historical persons: the focus of this talk. The other two ontologies – for historical sources and for places, would be presumably rich and complex too, and although the OHC might make use of some of their classes because much of the work of prosopography involves sources and places, we wouldn&apos;t want to duplicate their conceptual model in the OHP. Our prosopographical project (the red box in the middle) would be creating digital surrogate instances for People, Assertions, and the various other classes that are defined in the OHC. We’ve heard here about co-reference, but it has tended to focus on the co-referencing of things – of a particular person for example. Ontologies provide a different way to think about co-reference from what we have mainly heard here. The place of ontologies in the semantic web is rather subtle, and it supports rather different possible roles for an OHP in any particular prosopographical project. In the same way that there are two and a half different ways that an museum might relate its data to CIDOC-CRM, these projects might relate the model of their data in two and half different ways too. A prosopographical project might model its structure directly from that defined by the OHC, or, second, it might already have a model for its data, in which case it could use ontology tools to map its own entities as far as possible to those in the OHC. In addition, it might well subclass OHC entities to enrich the vocabulary to meet its own specialised needs. Identifying people in history requires connections with historical documents, and, if there was a good online repository for the sources it was working with, it would not need to duplicate any of that repository&apos;s data but merely point to it in good Linked Data fashion. In a similar way, if there was a good repository of places (e.g. Pleiades) that covered the area the prosopography worked on, it could simply reference materials in it. Like any good concept reference model, or computer ontology, the OHC would consist primarily of class and property definitions. The boxes represent some of the conceptual entities an OHC might represent – but they are not meant here to be read too formally! Since it is representing prosopography work, one would expect one of the classes to be Persons. Call me conservative here, but I like the word &quot;Person&quot; rather than &quot;Agent&quot; or &quot;Actor&quot;, since both these terms imply a kind of active role that might fit with events a person is involved in, but fits less well with assertions that give the person attributes (states, or traits, to use TEI&apos;s terminology). Sometimes a person is in fact a Group of people – a legal entity say. CIDOC-CRM&apos;s approach to the handling of Groups could fit well here. People have names, and often more than one name. Here, CIDOC-CRM&apos;s appellation model is helpful. There will likely be a canonical name that will be attached to the person, but there is also likely to be variants on these names that are revealed by the sources, and I think they should be dealt with as a kind of Trait for the person. All prosopographical work aims to make claims about the people it detects. Perhaps, indeed, it is possible to characterise a prosopography as a set of persons and a set of assertions about them. Here, I call these claims &quot;assertions&quot;, and, as in our &quot;factoid&quot; model, the assertions come out of an historian’s understanding of the sources that the project has worked with. Assertions can be thought of as several different kinds. Names as they appear in the sources I’ve already touched on, but prosopography is often interested in sorting out people’s place in society, and thus all of our Prosopographies, and perhaps most others too, are interest in offices, titles, or occupations people are reported as holding. These are also best thought of in terms of TEI&apos;s states/traits. People will also be associated with events by the role they have in them. In most of our prosopographies, sources also connect people to possessions and places, and most define a whole range of kinds of relationships (family, legal, etc.) between individuals. One other task, and one that our historian colleagues often don&apos;t expect, is that they find it useful to define and manage associated authority lists. Whether this is a list of the offices or titles that are used in the target society, or perhaps the kind of events that the target society recognises, authority lists become intellectual products of the prosopographical work as well as the list of persons. In the same way that a prosopography might expect to become an authority for the persons for its society that other projects can then reference through its URIs, it might find itself becoming an authority for these other authority lists that it has created. Thus, elements of the OHC to facilitate the management of authority lists would be useful.
- So, I hope I have successfully explained why an Ontology for Historical Persons might be useful, and gave you some preliminary sense of what it might be like. As you have probably guessed, however, I currently have no OHP. Why, if it is such a good idea, have I not built it, and then come to you to talk about it? This is because I believe that the OHP, if it is to have any hope of being useful and adopted, must have a kind of community engagement and approval. I could formalise our work on prosopography into a kind of global model. However, in the same way that CIDOC-CRM, if it was to be useful, had to be created as a collaborative project so that it represented a range of different perspectives around a common domain as well as possible, the OHP would need to be built collaboratively so that it properly represented other perspectives on prosopography beyond our own at DDH. So, where does this collaboration come from? CIDOC-CRM has been blessed with an organisation that is associated with its domain: the International Council of Museums, and one that was able to support and then promote its development. Unfortunately, Prosopographers are not so well organised! In this situation, then, how could one move towards getting the creation of an OHP underway? With presentations like this, then, I mean to explore whether there is interest in the idea, and see who might want to be involved in building it. I am also giving a similar presentation to this at the annual international Digital Humanities conference in Lincoln, Nebraska in July. I have informally spoken about the idea to various prosopographical partners, and to people involved in other prosopographical projects that are aware of our work at DDH. I’ve also had a brief word about it with some people associated with the TEI. If there is interest, I&apos;d expect that it would be possible to arrange a workshop to bring people together to develop the ideas further. So, what do you think?