Holy Islands: Monks, Hermits and the Edge of the World. Island Monasteries in Wikidata, Mapped Through Time

Early medieval monks of the Atlantic edge of Europe are famous for seeking islands, from Iona and Lindisfarne to Bardsey and Skellig Michael. I test how distinctive that was using the 20,228 monasteries, abbeys, priories, convents, friaries and hermitages in Europe that Wikidata records with coordinates, placing each on the GSHHG full-resolution shoreline and treating land under 1,000 km² as island and Great Britain, Ireland and larger islands as mainland. 459 houses (2.3%) stand on islands: 414 at sea and 45 in lakes and rivers. Among the 7,071 houses with a foundation date, the island share falls from 4.3% before 800 to 1.1% for 1100 to 1299 and 1.2% thereafter. On the Atlantic Celtic edge (Ireland, Scotland, Wales, Brittany, Galicia), 3 of 28 houses dated before 1100 are on islands (10.7%, 95% interval 3.7 to 27.2%), against 5 of 3,230 (0.2%) founded in France and Central Europe from 1100. The island houses furthest from the mainland are the early modern convents of the Azores, up to 1,656 km out. Of 2,944 dated closures, 614 fall in England and Wales in 1536 to 1541; the Viking raids leave no trace in the record. Coverage is very uneven: only 35% of houses are dated and Germany holds 24% of them. Interactive version: https://maps.tristanhotham.com/holy-islands/. Data and code: https://github.com/Tristan-Hotham/holy-islands. Blog post: https://blog.tristanhotham.com/2026/10/31/holy-islands/.