The Northern Crusades were a series of military campaigns in the late 12th to 14th centuries aimed at converting the pagan peoples of the Baltic region to Christianity. These campaigns primarily involved the Teutonic Knights, a Catholic military order, and other Christian forces from Germany and Scandinavia. The crusades targeted areas such as modern-day Estonia, Latvia, and Lithuania. The Northern Crusades were marked by battles, alliances, and the establishment of Christian states. The campaigns led to the spread of Christianity in the region and the eventual decline of pagan beliefs. They also contributed to the expansion of German influence in Eastern Europe.