 The main sources of the crusade, the legend of Saint Erik and the legend of Saint Henry, describes that the reason for the crusade were the multiple raids that pagan Finns made to Sweden.The crusade has traditionally been seen as the first attempt of the Catholic Church and Sweden to convert pagan Finns to Christianity.However, the Christianisation of the South-western part of Finland is known to have already started in 10th century, and in the 12th century, the area was probably almost entirely Christian.