This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The Northern Crusades are a collective term historians use for the series of papally sanctioned campaigns waged by Danish, Swedish and German crusaders, chiefly the Livonian Brothers of the Sword and, later, the Teutonic Knights into which the Brothers were absorbed, against the pagan Wendish, Baltic and Finnic peoples of the southern and eastern Baltic shore. The campaigns began with the 1147 Wendish Crusade, authorized alongside the Second Crusade to the Holy Land, and went on to conquer and forcibly convert the Livonians, Estonians and Old Prussians, continuing against pagan Lithuania into the early fifteenth century, well over two hundred years after the campaigns first began.
The Kingdom of Denmark and the Kingdom of Sweden fought alongside the military orders throughout this long span of campaigns. The result was a lasting territorial and religious transformation of the eastern Baltic: the conquered Wendish, Livonian, Estonian and Old Prussian peoples were forcibly converted to Latin Christianity, and the military orders that led the campaigns established durable states, the Ordensstaat of the Teutonic Knights and the Livonian Order, that governed the region for centuries after the fighting itself had ended and the last pagan resistance had been broken.