The Northern Crusades[1] or Baltic Crusades[2] were Christianization campaigns undertaken by Catholic Christian military orders and kingdoms, primarily against the pagan Baltic, Finnic and West Slavic peoples around the southern and eastern shores of the Baltic Sea.
The most notable campaigns were the Livonian and Prussian crusades. Some of these wars were called crusades during the Middle Ages, however others, including the 12th century First Swedish Crusade and several following military incursions by Scandinavian Christians against the then pagan Finns, were dubbed "crusades" only in the 19th century by romantic nationalist historians. However, crusades against Estonians and against "other pagans in those parts" were authorized by Pope Alexander III in the crusade bull Non parum animus noster,[3] in 1171 or 1172.[4]