History of Finland
The history of Finland begins around 9,000 BC during the end of the last glacial period. Stone Age cultures were Kunda, Comb Ceramic, Corded Ware, Kiukainen, and Pöljä cultures. The Finnish Bronze Age started in approximately 1,500 BC and the Iron Age started in 500 BC and lasted until 1,300 AD. Finnish Iron Age cultures can be separated into Finnish proper, Tavastian, and Karelian cultures. The earliest written sources mentioning Finland start to appear from the 12th century onwards when the Catholic Church started to gain a foothold in Southwest Finland.
Finland–Sweden relations
During the 11th and 12th centuries, Sweden gradually became a unified Christian kingdom. According to the archaeological finds, Christianity first gained a foothold in Finland during the 11th century as well. Later medieval legends describe Swedish attempts to conquer and 'christianize' Finland by the First Swedish Crusade sometime in the mid-1150s. In the early 13th century, Bishop Thomas became the first bishop of Finland. There were several secular powers who aimed to bring Finland under their rule but the Swedish regent Birger Jarl established Swedish rule in Finland through the Second Swedish Crusade, which is most often dated at 1249.