09-19-2021-0632 - Prussian Crusade 13th-century 1217 1274 (50 year)

 The Prussian Crusade was a series of 13th-century campaigns of Roman Catholic crusaders, primarily led by the Teutonic Knights, to Christianize under duress the pagan Old Prussians. Invited after earlier unsuccessful expeditions against the Prussians by Christian Polish kings, the Teutonic Knights began campaigning against the Prussians, Lithuanians and Samogitians in 1230. By the end of the century, having quelled several Prussian uprisings, the Knights had established control over Prussia and administered the conquered Prussians through their monastic state, eventually erasing the Prussian language, culture and pre-Christian religion by a combination of physical and ideological force. Some Prussians took refuge in neighboring Lithuania.

Prussian Crusade
Part of the Northern Crusades
Map of the Prussian clans in the 13th century.
Date 1217–1274 Location Modern-day Kaliningrad Oblast, Russiaand northeastern Poland Result Crusader victory Territorial changes Teutonic Knights gain control of Prussia

https://en.wikipedia.org/wiki/Prussian_Crusade