The Prussian Confederation is established on February 21, 1440, in Kwidzyn (Marienwerder) by 53 nobles/clergy and 19 cities to oppose the high taxes and authoritarian rule of the Teutonic Knights and seek autonomy within the Kingdom of Poland.
The Prussian Confederation requested incorporation into the Kingdom of Poland in 1454, triggering the Thirteen Years' War (1454–1466). The 1466 treaty resulted in the division of Prussia, creating "Royal Prussia" (under Polish sovereignty) and leaving the remaining Teutonic Order land as a Polish fief.
