Fürstbistum Ermland
In the Thirteen Years' War (1454–1466), the towns of the Prussian Confederation in Pomerelia and the adjacent Prussian region east of the Vistula River rebelled against the rule of the Teutonic Knights and sought the assistance of King Casimir IV Jagiellon of Poland. By the Second Peace of Thorn in 1466, Pomerelia and the Prussian Culm (') and Marienburg (Malbork) lands as well as the autonomous Prince-Bishopric of Warmia (') became the Polish province of Royal Prussia, which received special rights, especially in Danzig ('). The province became a Land of the Polish Crown within the Polish–Lithuanian Commonwealth (') by the 1569 Union of Lublin. Parts of the local population objected to the Union as being a biased and unlawful interpretation of the incorporation privilege of 1454.