In the Middle Ages, the inhabitants of the Duchy of Masovia were called "Mazur(z)y" in Polish. Between the 14th and 17th centuries, Polish settlers from northern Masovia moved to the southern territories of the Monastic State of the Teutonic Knights. (These lands had previously belonged to the Baltic Old Prussians, whom the Teutonic Knights had conquered in the 13th and 14th centuries.) The northern part of this state was soon settled by settlers from Germany and thus became Germanised. On the other hand, Protestants coming from the Duchy of Masovia, which was independent until 1526, partially Polonised a southern part of the Duchy of Prussia, later Kingdom of Prussia. Only in Allenstein, now Olsztyn, Catholics remained, because it belonged to the Prince-Bishopric of Ermland or Warmia.