Virtual Record Treasury of Ireland

Knowledge Graph

The Knowledge Graph for Irish History is a dynamic research tool enabling discovery of information about Ireland’s deep history. The Graph uses Linked Open Data technologies to make connections between datasets and archival collections, both within and beyond the Virtual Record Treasury. The Knowledge Graph for Irish History is a Five Star Linked Open Data resource—the first of this kind to exist for Irish historical research.

A New and Dynamic Way to Explore The Past

The power of the Knowledge Graph comes from its Semantic Web structure. The Graph can be imagined as an information network, in which historical data is organized into categories, classes and relationships. Unlike a conventional database, all data in the Knowledge Graph has a ‘meaning’ that a machine can interpret. In other words, raw information becomes knowledge—and this knowledge can power research and discovery. 

To date, the Knowledge Graph contains over 2.7 million linked data ‘triples’—meaningful statements—concerning people, places, offices, and organizations across Irish history. 

  • Search the Graph here
  • Explore the Graph using our ‘Advanced Tools’ below
  • Learn more about the Knowledge Graph by reading our Research Guide or watching our Demonstration videos below.


The Knowledge Graph for Irish History draws on curated datasets containing data on people, places, offices and organizations. Individual people and places mentioned in the Graph are known as ‘entities’. Every entity in the Graph has a unique resource identifier, or URI. The Knowledge Graph is a dynamic resource. As more historical entities are added, the Graph will continue to grow. 

Key datasets in the graph include:

  • Modern Place: over 60,000 modern place-names in a hierarchy of all counties, baronies, parishes and townlands in Ireland generating 1,450,640 triples
  • Early-Modern Place: approximately 44,000 early-modern place-names from seventeenth-century sources, interlinked with modern locations, generating 58,384 triples
  • Dictionary of Irish Biography: over 10,000 persons from the Dictionary of Irish Biography generating 581,596 triples
  • Medieval People: over 2,000 persons from c.1200-1500 generating 76,099 triples
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Key numbers

Early Modern Places
Modern Places
Links to the Linked Open Data cloud
Ontology Classes
Distinct Resources

Hidden Stories


A specific piece of information about a person, place, office, or organization entity. Attributes for a ‘person entity’ might include name, date of birth or religion, for example. 

A person, place, office, or organization extracted from the historical records. 

A period of time when a person was most active. Used in place of known birth and death dates.

Knowledge Graph
A network graph which organizes data in terms of different entities or concepts and connects their attributes and relationships with meaningful links.

Linked Data
A Knowledge Graph that is available on the Web and interlinked with additional external Knowledge Graphs, also on the Web.

A type of controlled vocabulary establishing a shared understanding of concepts, categories, and relationships within a subject area. 

Resource Description Framework (RDF)
A standard model for representing and linking structured information on the web, used by the Virtual Treasury to store knowledge graph data.

Schema: the framework for recording and organizing an entity’s attributes and relations. Each entity type has its own schema.

Structured data: data which conforms to a data model and has a well defined structure.

Subgraph: a smaller grouping of information within the Knowledge Graph.

Triple: <Subject, Predicate, Object> – a statement used to construct the knowledge graph by defining attributes and relationships

  • Subject – a thing, often an entity
  • Predicate – defines the relationship between the subject and the object 
  • Object – the entity or attribute related to the subject

Vocabulary: a formal standard for the entity types and relations. It is usually seen as a lightweight version of an ontology.

Team and Acknowledgements

The Knowledge Graph for Irish History was designed and implemented at the ADAPT Centre by Dr Fabrizio Orlandi and Professor Declan O’Sullivan, building on foundations by Dr Christophe Debruyne.

Technical contributions were also made by Dr Gary Munnelly, Technical Lead on the Beyond 2022 Project, and Maraim Masoud, Senior Reearch Engineer.

The Knowledge Graph Lead for Humanities was Dr Lynn Kilgallon.

Dr Peter Crooks and Dr David Brown contributed curated datasets and provided expert guidance on medieval and early modern history.

The team gratefully acknowledges the partnership of the Dictionary of Irish Biography (Royal Irish Academy) and the advice of Turlough O’Riordan, online and digital editor for the DIB.


Declan O’Sullivan, ADAPT, School of Computer Science and Statistics, Trinity College Dublin
Fabrizio Orlandi, ADAPT, School of Computer Science and Statistics, Trinity College Dublin
Gary Munnelly, ADAPT, School of Computer Science and Statistics, Trinity College Dublin
Christoph Debruyne (formerly ADAPT), Assistant Professor, Montefiore Institute, Liège University
Maraim Masoud (formerly ADAPT) 

Peter Crooks, Department of History, School of Histories and Humanities, Trinity College Dublin
Lynn Kilgallon, Department of History, School of Histories and Humanities, Trinity College Dublin
David Brown, Department of History, School of Histories and Humanities, Trinity College Dublin

Professor Robin Frame and Dr Beth Hartland of the English Landholding Project at Durham University generously provided access to their database of medieval Irish place-names.
Turlough O Riordáin generously provided access to data drawn from The Dictionary of Irish Biography, a project of the Royal Irish Academy. 

The Irish Manuscripts Commission generously provided access to the late Dr Philomena Connolly’s calendar of Irish Exchequer Payments (Dublin, 1998), which was used to develop the medieval component of the Knowledge Graph.