Northern Crusades
The Northern Crusades or Baltic Crusades were crusades undertaken by the Christian kings of Denmark, Poland and Sweden, the German Livonian and Teutonic military orders, and their allies against the pagan peoples of Northern Europe around the southern and eastern shores of the Baltic Sea. Swedish and German Catholic campaigns against Russian Eastern Orthodox Christians are also sometimes considered part of the Northern Crusades.
Some of these wars were called crusades during the Middle Ages, but others, including most of the Swedish ones, were first dubbed crusades by 19th-century romantic nationalist historians. The East Baltic world was transformed by military conquest: first the Livs, Latgallians and Estonians, then the Semigallians, Curonians, Prussians and Finns proper, Tavastians and Karelians underwent defeat, forced baptism, military occupation and sometimes extermination by groups of Danes, Germans and Swedes.
Background
The official starting point for the Northern Crusades was Pope Celestine III's call in 1193; but the Christian kingdoms of Scandinavia, Poland and the Holy Roman Empire had begun moving to subjugate their pagan neighbors even earlier. The non-Christian people who were objects of the campaigns at various dates included: