Treaty of Kalisz (1343)

The Treaty of Kalisz (Pokój kaliski, Vertrag von Kalisch) was a peace treaty signed by King Casimir III the Great of Poland and the Teutonic Knights on 2 June 1343 in Kalisz.

It concluded the Polish-Teutonic War (1326–1332). The Polish king had to renounce claims to Chełmno Land and Gdańsk Pomerania (Pomerelia). In exchange, Poland regained Kuyavia and the Lands of Dobrzyń. The Polish side also acknowledged other territorial acquisitions of the Order, e.g. those gained by the Treaty of Soldin.

However, King Casimir (and subsequently his successors) did not stop using the title of Duke of Pomerania. This was based on a separate clause of the treaty which did recognize that he had previously been the suzerain of the concerned lands. Additionally, in the treaty Poland did not recognize the right of the Order to the lands, leaving their status in a legal limbo; Poland had renounced its claims, but it did not recognize those of the Order.

As part of the treaty, the king of Poland also became a patron of the Order, which was obliged to aid Poland militarily, and make symbolic feudal payments. In practice, this meant that if the Order ever went to war against the Polish kings, it would lose all rights to the lands which were subject of the treaty. As a result, while Pomerelia remained a subject of contention, the treaty was followed by a 66-year span of peace, until the conflict erupted again in the Polish–Lithuanian–Teutonic War of 1409. By the Second Peace of Thorn in 1466, the Polish crown regained the Pomerelian lands, which were then incorporated into Royal Prussia.