The Treaty of Kalisz (1343), also known as the Peace of Kalisz, was a peace treaty signed on July 8, 1343, in Kalisz, Poland, between King Casimir III of Poland and the Teutonic Order. It formally concluded a series of conflicts and wars between the Kingdom of Poland and the Teutonic Knights that had been ongoing for decades, primarily concerning control over Pomerelia (Gdańsk Pomerania) and other territories.
The treaty saw Casimir III renounce all claims to Pomerelia, including Gdańsk (Danzig), Chełmno Land, and Michałów Land, which had been lost to the Teutonic Knights in previous conflicts. In return, the Teutonic Order relinquished Kujawy and Dobrzyń Land, which they had occupied. While Casimir III renounced claims to Pomerelia, he was allowed to retain the title "Duke of Pomerania," a title which was largely symbolic.
The Treaty of Kalisz provided a period of relative peace and stability between Poland and the Teutonic Order for several decades, although the underlying tensions remained. It also significantly impacted the political landscape of the region and shaped the future relations between Poland, the Teutonic Order, and the various duchies and territories in the Baltic Sea area. This treaty was a significant diplomatic event in 14th-century Eastern Europe, impacting the balance of power and setting the stage for future conflicts and alliances.