 Complete the following phrase:  The bulk of the ancestral lands of the Baltic Old Prussians were enclosed within East Prussia. During the 13th century, the native Prussians were conquered by the crusading Teutonic Knights. After the conquest the indigenous Balts were gradually converted to Christianity. Because of Germanization and colonisation over the following centuries, Germans became the domit ethnic group, while Masurians and Lithuanians formed minorities. From the 13th century, East Prussia was part of the monastic state of the Teutonic Knights. After the Second Peace of Thorn in 1466 it became a fief of the Kingdom of Poland. In 1525, with the 