Treaty of Labiau

Treaty of Labiau

Labiau castle
Type	Legal status of the Duchy of Prussia
Signed	20 November 1656
Location	Labiau castle (now Polessk)
Signatories	Charles X Gustav of Sweden Frederick William I of Brandenburg
Parties	Swedish Empire House of Hohenzollern
Language	Latin

The Treaty of Labiau was a treaty signed between Frederick William I, Elector of Brandenburg and Charles X Gustav of Sweden on 10 November (O.S.)^[1] / 20 November (N.S.) 1656 in Labiau (now Polessk). With several concessions, the most important being the elevation of Frederick William I from a Swedish vassal to a full sovereign in the Duchy of Prussia and in Ermland (Ermeland, Warmia), Charles X Gustav strove to "buy Frederick William's support" in the ongoing Second Northern War.^[2]