Whose Church Is It? Church Dedications and Holy Wells across Western Europe

Which saint is each church dedicated to, and what geography does that reveal? I assign a dedication to 208,005 of 279,212 church buildings recorded in Wikidata for twelve Western European countries, using the structured property 'dedicated to' where it exists (47,902 churches) and otherwise a multilingual parser of church names, which agrees with the structured property for 96.3% of the 41,574 churches where both are available. Because coverage differs greatly between countries, all results are shares within countries and regions. Mary is the leading dedication in every country, from 9% of churches in Luxembourg to 38% in Portugal, and leads in 85% of 20 km hexagons. Setting Marian and Christological dedications aside, Peter, John and Martin lead in 30%, 22% and 13% of hexagons, with Martin concentrated in northern France. Early Celtic saints hold 22% of Irish churches, and Cornwall is the most varied region, with 66 distinct dedications per 100 churches against 23 in the Algarve. Many local saints have every church in their country within one region. Two popular associations hold only in part: James is commoner near Santiago within Spain but shows little gradient beyond it, and in Britain and Ireland St Michael's churches stand higher above sea level but not more often on local high points. In Ireland, Brigid holds 23% of named holy wells but 3.3% of churches. Interactive version: https://tristan-hotham.github.io/saints-and-wells/. Data and code: https://github.com/Tristan-Hotham/saints-and-wells. Blog post: https://blog.tristanhotham.com/2026/10/27/saints-and-wells/.