Polish–Teutonic War (1519–21)

Polish–Teutonic War of 1519–1521
Date 1519–1521 Location Monastic State of the Teutonic Knights Result Treaty of Kraków
Belligerents
Teutonic Knights	Kingdom of Poland
Commanders and leaders
Albert of Hohenzollern	Sigismund I the Old Mikołaj Firlej Nicolaus Copernicus
Strength
tens of thousands, but likely under 50,000	tens of thousands, but likely under 50,000

The Polish–Teutonic War of 1519–1521 (German: Reiterkrieg, horsemen's war, Polish: Wojna pruska, Prussian War) was fought between the Kingdom of Poland and the Teutonic Knights, ending with an armistice in April 1521. Four years later, under the Treaty of Kraków, part of the Catholic Monastic state of the Teutonic Knights became secularized as the Duchy of Prussia. The reigning Grand Master Albert of Hohenzollern-Brandenburg-Ansbach became the first Duke of Prussia by paying the Prussian Homage as vassal to his uncle, Polish king Sigismund I the Old.

After the Second Peace of Thorn (1466), the Teutonic Order was under Polish suzerainty. In the late 1490s, the Order developed the idea of electing only an Imperial Prince as future Grand Master, who as subject to the Emperor could resist having to pay homage to Kings of Poland. The Order was present not only in Prussia but throughout the Empire, and it was also subordinate to the Holy Roman Emperor, who had objected since 1501 to Duke Frederick of Saxony, Grand Master of the Teutonic Order and Reichsfürst, offering tribute to the Polish king.

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