Northern Crusades

The Northern Crusades are a broad term for military campaigns by Christan against various pagan people in the Baltics. Several of the campaigns were agitated when some of the local tribes killed the priests and converts of the Christan religion. The Northern Crusades happened around the same time as their more famous counterparts against the Muslims in the Middle East. Most of the Christan nations that waged the Baltic Crusades were Denmark, Poland, and Sweden. The Baltic region was one of the very few parts of Europe that remained Pagan. So the Christan kingdoms in Scandinavia often waged various campaigns against the indigenous Pagan tribes. Like the later and more famous colonial period, the Christians relied on the local tribes (after being theoretically "Christianized") to fight against other tribes that were rivals of their collaborators. Warfare was not of any large battles as you see in the more famous Middle Eastern crusades due to the swampy environment. Instead it was more of raids and ambushes, with the occasional siege of a small fort.