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Pelagios: linking the places of our past


Investigative team

  • Project Director: Leif Isaksen, History, Lancaster University
  • Community Director: Elton Barker, Classical Studies, The Open University
  • Technical Director: Rainer Simon, The Austrian Institute of Technology
  • Developer: Andrew Lindley, The Austrian Institute of Technology
  • Community Manager: Pau de Soto, Institute of Catalan Studies, Barcelona



What is Pelagios Commons?

Pelagios Commons is a (i) community and (ii) infrastructure for Linked Open (geo) Data (LOD) in the Classical World and the Humanities more broadly. The basic premise of LOD is that, wherever possible, online information resources should be connected to related content. While this occurs to some extent with standard HTML hyperlinks, they provide only unilateral links between specific documents. The technologies behind LOD allow us to introduce meta-links that create multi-lateral connections between clusters of content related to a specific concept. Pelagios focuses on geographic concepts, and brings together historical materials associated with particular places.

(i) Community

Pelagios Commons operates through the activity of multiple Special Interest Groups (SIGs). Each of these SIGs host forums dedicated to the discussion of the challenges facing both communities working on particular historical periods and those developing the resources for discovering and representing historical geography. All are welcome to sign up to the SIG (or SIGs) of their choosing: no technical experience is required (although techies are extremely welcome too!). SIGs also play an important role in the governance of Pelagios through its Commons Committee. The 10 current SIGs are: Historical periods: ancient Greek; Roman; Medieval, Byzantine and Islamic; East Asian; Modern (post-1500) Technical: Maritime; Micro-region; Gazetteer; Archaeological; Linked Pasts

(ii) Infrastructure

In order to help the community create links and make use of them, Pelagios Commons is developing open resources for both the production and consumption of LO(geo)D.

Recogito is a Web-based tool that makes it easy to identify and record the places referred to in historical texts, maps and tables. Recogito has features dedicated to both stages of the annotation workflow: - a geotagging area, for identifying place names in digital texts, tabular documents or high-resolution maps; - a georesolving area, for mapping those place names to a global gazetteer, supported by an automated suggestion system. Recogito also provides basic features for cataloguing and managing documents and their metadata, as well as viewing annotations, usage statistics and bulk-downloading annotation data.

Peripleo is a map-based search engine for exploring data annotated by the Pelagios community. Its user interface allows for free browsing as well as keyword and full-text search, while offering filtering options based on time, data source and object type. Data ranges from antiquity until 1500 AD and from Europe to East Asia (there is currently no content from sub-Saharan Africa or the Americas). It includes archaeological, textual and image-based content. Data remains hosted at source and is detected based on annotations produced by content curators or third parties. It is continually growing – for up-to-date information see our live list.

Pelagios map tiles depict notable place names (settlements, regions and physical features) against a high resolution topography for a range of historical periods. They are released under open license for use in other applications and services, providing a contextual backdrop for historical data.


Established in 2011, Pelagios has been developing the means of linking independently created and curated online resources together via their common references to place. In its first two phases, Pelagios worked with major partners specialising in different areas of the classical world—e.g. the Perseus Classical Library, the German Archaeological Database,, the Pleiades gazetteer—to develop a simple but effective means of linking between their varying resources. In phase 3, we extended our work to encompass "Early Geospatial Documents" more broadly, including early Christian Mappae Mundi and pilgrimages, Portolan charts, and Islamic and Chinese maps. This centred on developing a user-friendly platform (Recogito) for annotating documents (both texts and maps), and trialling a map interface (Peripleo) for searching through the network. Pelagios 4 worked with scholars from these different traditions to test the extent to which digital tools could facilitate geospatial analysis, and encourage reflection on the process of annotation itself. Pelagios 5 ("Sea Change") trialled crowdsourcing annotation in university undergraduate classes.

The research output by Pelagios is having a significant impact in the development of ancient world web-infrastructure for academic and non-academic data providers alike. The open data service technology it has championed is now the de facto international standard for open linked geospatial data concerning the ancient world, and is being used by other Web and linked data projects (e.g. Standards for Networking Ancient Prosopographies; PeriodO: a gazetteer for period assertions). Impact is measured not just by the growing number of partners whom Pelagios has attracted but also by the process that each group undertakes to become a partner: by aligning their data to the Pelagios network, each partner changes the way they hold their data. This means that Pelagios’s research is transforming both the nature of these data and the way in which these organisations work or even conceptualise their activity.

  • Pelagios phases 1 and 2 was funded by JISC in successive programmes: Geospatial and Community Outreach and Resource Discovery (2011-2012)
  • Pelagios phase 3: "Early Geospatial Documents" was funded by The Andrew W. Mellon Foundation (2013-2015)
  • Pelagios phase 4: "Studying the places of our past through the documents that refer to them" was funded by the AHRC (2014-2015)
  • Pelagios phase 5: "Sea Change" was supported with funding from Open Knowledge Foundation (2014-2015)
  • Pelagios phase 6: "Pelagios Commons" is currently supported with funding from The Andrew W. Mellon Foundation (2016-2018)


  • Simon, R., Barker, E. and Isaksen, L. (2012a): Exploring Pelagios: a visual browser for geo-tagged datasets. In: Agirre et al. (eds.), International Workshop on Supporting Users' Exploration of Digital Libraries. Cyprus, 29-34
  • Simon, R., Barker, E. and Isaksen, L. (2012b): Exploring Pelagios: a visual browser for geo-tagged datasets. In: International Workshop on Supporting User's Exploration of Digital Libraries, Paphos, 29-34.
  • Isaksen, L., Simon, R., Barker, E., and de Soto Cañamares (2014): Pelagios and the emerging graph of ancient world data. Web Sci’14: Proceedings of the 2014 ACM conference on Web science, 197-201.
  • Simon, R., Pilgerstorfer, P., Isaksen, L. and Barker, E. (2014): Towards semi-automatic annotation of toponyms on old maps. e-Perimetron, 9.3, 105-112 (
  • Simon, R., Barker, E., de Soto Cañamares, P. and Isaksen, L. (2014a): ‘Pelagios’. ISAW Papers 7.27.
  • Simon, R., Barker, E., de Soto Cañamares, P. and Isaksen, L. (2014b): Pelagios 3: Towards the semi-automatic annotation of toponyms in Early Geospatial Documents. In Proceedings of Digital Humanities 2014. Lausanne, Switzerland, July 8-12, 2014.
  • Simon, R., Barker, E., Isaksen, L. and de Soto Cañamares, P. (2015): Linking early geospatial documents, one place at a time: annotation of geographic documents with Recogito. e-Perimetron. 10.2, 49-59. ISSN 1790-3769.
  • Simon, R., Isaksen, L., Barker, E., and de Soto Cañamares, P. (In Press). The Pleiades gazetteer and the Pelagios project. In M. L. Berman, R. Mostern H. Southall, eds. Placing Names: Enriching and Integrating Gazetteers, Indiana.