in 1295 by the coronation of Duke Przemysł II of Greater Poland, the Duchy of Masovia remained independent. Upon the death of Duke Boleslaus II in 1313, Masovia was divided among his sons: Siemowit II became Duke at Rawa (until 1345) Trojden I became Duke at Czersk (until 1341) Wenceslaus became Duke at Płock (until 1336), followed by his son Bolesław III (until 1351) As neither Siemowit II nor Bolesław III of Płock left any heirs, Trojden's son Duke Siemowit III (1341–1381) was able to re-unite most of the Masovian lands under his rule; in 1351 he and his brother Casimir became vassals of the Polish kings, while the Bishopric of Płock had always been part of the Polish Archdiocese of Gniezno. Upon Siemowit's III death in 1381 however, Masovia was again partitioned between his sons: Janusz I, ruled as duke at Czersk until 1413, when he moved his residence to Warsaw, followed by his grandson Duke Boleslaus IV (1429–1454) Siemowit IV, Duke at Rawa and Płock (until 1426), also Duke of Belz from 1388 Since the Polish-Lithuanian Union of 1385, Masovia was localized between the joined Jagiellonian states. The Dukes of Masovia also ruled the Duchy of Belz until 1462. After the establishment of the Rawa and Płock Voivodeships, in 1495 the last surviving son of Boleslaus IV, Duke Konrad III Rudy, once again united the remaining Masovian lands under his rule. However, the male line of the Masovian Piasts became extinct upon the death of his son Duke Janusz III in 1526, whereafter the duchy as a reverted fief became the Masovian Voivodeship of the Polish Crown. Parts of the southern region of neighboring East Prussia received settlers and Protestant religious refugees who became known as the Mazurs. By the 18th century the portion of East Prussia in which they settled was sometimes referred to as Masuria (Masuren), and inhabited by a Protestant population of Germans and Poles. Partitions of Masovia The Duchy went through various border changes in the coming years, sometimes losing and sometimes gaining territory. See also Duke of Masovia Notes References 12th-century establishments in Poland Duchies of Poland Duchy of Masovia Former monarchies of Europe States and territories established in 1138 States and territories disestablished in 1526 History of Masovian Voivodeship Fiefdoms of Poland Former duchies Former principalities