Northern Crusades (1147–1410)
The Third Swedish Crusade to Finland was a Swedish military expedition against the pagan Karelians in 1293. It followed the First Crusade and the Second Crusade to Finland. As the result of the attack, Viborg Castle was established and western Karelia remained under Swedish rule for over 400 years. The name of the expedition is largely anachronic, and it was a part of the Northern Crusades.
According to Eric Chronicles, the reason behind the expedition was pagan intrusions into Christian territories. Birger Magnusson's letter of 4 March 1295 states that the motive of the crusade was long-time banditry and looting in the Baltic Sea region by Karelians, and the fact that they had taken Swedes and other travellers as captives and then tortured them. Karelians had also been engaged in a destructive expedition to Sweden in 1257 which led Valdemar to request Pope Alexander IV to decleare a crusade against them, which he agreed.
According to Eric Chronicles, Swedes conquered 14 hundreds from the Karelians.