During the Northern Crusades against the pagan Balts and Slavs of northern Europe, forced conversions were a widely used tactic, which received papal sanction. These tactics were first adopted during the Wendish Crusade, but became more widespread during the Livonian Crusade and Prussian Crusade, in which tactics included the killing of hostages, massacre, and the devastation of the lands of tribes that had not yet submitted. Most of the populations of these regions were converted only after the repeated rebellion of native populations that did not want to accept Christianity even after initial forced conversion; in Old Prussia, the tactics employed in the initial conquest and subsequent conversion of the territory resulted in the death of most of the native population, whose language consequently became extinct.