St. Ludger's Abbey
Helmstedt, Germany
St. Ludger's Abbey (Kloster St. Ludgeri) was a former monastery of the Benedictine Order in Helmstedt, Lower Saxony, founded by Saint Ludger around 800. Until it was secularised in 1802 it was an Imperial Abbey, with sovereignty over the whole town of Helmstedt until the 15th century.
Church data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).