Pleiades is a community-built gazetteer of ancient places, with locations, names and sources for towns, forts, ports and sites across the ancient world. Our cities layer takes its Roman places from it.
Key takeaways
- Pleiades describes itself as a community-built gazetteer and graph of ancient places, built by volunteers and peer reviewed [1].
- Our cities layer holds 9,348 Roman places taken from it.
- Its content is shared under a Creative Commons Attribution licence, so it must be credited [1].
- A dot on the map is a place the gazetteer records, not a measure of how big or important it was.
How the Pleiades gazetteer works
A gazetteer is a directory of places. Pleiades is a gazetteer of the ancient world. It calls itself a community-built gazetteer and graph of ancient places, publishing information about ancient places and spaces for people, search engines and research tools [1]. Each entry gives a place its names, its location and the sources that support them, so that scholars can say they are all talking about the same site.
It is built by volunteer contributors, and their work is peer reviewed. The National Endowment for the Humanities has given significant periodic support since 2006, the Ancient World Mapping Center at the University of North Carolina at Chapel Hill has supported it since 2000, and New York University's Institute for the Study of the Ancient World has hosted it since 2008 [1]. Its content is shared under a Creative Commons Attribution licence, though individual contributors hold the copyrights [1].
Coverage is uneven. The strongest is in Western Europe, North Africa, the Nile Valley and Southwest Asia, with partial coverage in Central Asia, the Horn of Africa and the Indian Subcontinent [1]. That matters for a Roman map: some regions of the empire have denser and better-checked records than others, so a thin area on the map can reflect the research as much as the ancient world.
Pleiades connects well with other ancient-world datasets. The Ancient World Mapping Center publishes its own open map data, such as roads, coastlines and rivers [2], and the two projects share a long working relationship.
An example from our data
Our cities layer holds 9,348 Roman places taken from Pleiades, spread across the 45 modern countries inside the empire at its peak. At country level, Italy has 1,043, France has 728, Spain has 588 and the United Kingdom has 173.
Those counts say how many places the gazetteer records within each country's modern borders, not how many Roman cities there ever were or how large they were. A tiny road station and a great port each count as one dot. Full credits are on our data sources page.
The thing people get wrong
It is tempting to read the cities layer as a list of Roman cities and to compare countries by their totals. The layer is a list of recorded places, shaped by how much research and fieldwork each region has had. A country with fewer dots may simply have been studied less, or have had a sparser pattern of settlement. Treat the totals as a guide to the gazetteer, not a census of the ancient world.
Frequently asked questions
Who runs Pleiades?
Volunteer contributors build it and their work is peer reviewed. The Ancient World Mapping Center at the University of North Carolina has supported it since 2000, and New York University's Institute for the Study of the Ancient World has hosted it since 2008.
Can I reuse Pleiades data?
Yes, under a Creative Commons Attribution licence, as long as you credit it. The licence terms are on the Pleiades site.
Are all Pleiades places Roman cities?
No. It records ancient places of many kinds and periods. Our layer picks out the Roman places inside the area the map covers.
Sources
- Pleiades, Pleiades (Institute for the Study of the Ancient World and others).
- AWMC geodata, Ancient World Mapping Center (GitHub).
- Every figure from our own map is worked out from the datasets on the data sources page (checked against Ancient World Mapping Center outlines and Pleiades).