By the Second Peace of Thorn (1466), Warmia was awarded to the Polish Crown as part of Royal Prussia, though with considerable autonomy, while Masuria became part of a Polish fief, first as part of the Teutonic state, and from 1525 as part of the secular Ducal Prussia. Prussia took direct control of the region in the First Partition of Poland (1772) and in 1773 included the area in the newly formed province of East Prussia. It formed the southern part of the province after World War I, becoming part of Poland after World War II, with northern East Prussia going to the Soviet Union to form the Kaliningrad Oblast.