By the mid-twelfth century the lands on the eastern coast of the Baltic Sea, from Finland to the frontiers of Poland, were Catholic Europea s final frontier: a vast, undeveloped expanse of lowlands, forest and waters, inhabited by peoples belonging to the Finnic and Baltic language groups. In the course of the following three centuries, Finland, Estonia, Livonia and Prussia were incorporated into the Latin world through processes of conquest, Christianisation and settlement, and brought under the rule of Western monarchies and ecclesiastical institutions. Lithuania was left as the last pagan...