The First Peace of Thorn is signed in Thorn (Toruń), Monastic State of the Teutonic Knights (Prussia).

The (First) Peace of Thorn was a peace treaty formally ending the Polish–Lithuanian–Teutonic War between allied Kingdom of Poland and Grand Duchy of Lithuania on one side, and the Teutonic Knights on the other. It was signed on 1 February 1411 in Thorn (Toruń), one of the southernmost cities of the Monastic State of the Teutonic Knights. In historiography, the treaty is often portrayed as a diplomatic failure of Poland–Lithuania as they failed to capitalize on the decisive defeat of the Knights in the Battle of Grunwald in June 1410. The Knights returned Dobrzyń Land which they captured from Poland during the war and made only temporary territorial concessions in Samogitia, which returned to Lithuania only for the lifetimes of Polish King Władysław Jagiełło and Lithuanian Grand Duke Vytautas. The Peace of Thorn was not stable. It took two other brief wars, the Hunger War in 1414 and Gollub War in 1422, to sign the Treaty of Melno that solved the territorial disputes. However, large war reparations were a significant financial burden on the Knights, causing internal unrest and economic decline. The Teutonic Knights never recovered their former might.

Toruń is a city on the Vistula River in north-central Poland and a UNESCO World Heritage Site. Its population was 196,935 as of December 2021. Previously, it was the capital of the Toruń Voivodeship (1975–1998) and the Pomeranian Voivodeship (1921–1945). Since 1999, Toruń has been a seat of the local government of the Kuyavian-Pomeranian Voivodeship and is one of its two capitals, together with Bydgoszcz. The cities and neighboring counties form the Bydgoszcz–Toruń twin city metropolitan area.

The State of the Teutonic Order was a theocratic state located along the southeastern shore of the Baltic Sea in northern Europe. It was formed by the knights of the Teutonic Order during the early 13th century Northern Crusades in the region of Prussia. In 1237, the Livonian Brothers of the Sword merged with the Teutonic Order of Prussia and became known as its branch – the Livonian Order. At its greatest territorial extent during the early 15th century, the State encompassed Chełmno Land, Courland, Gotland, Livonia, Estonia, Neumark, Pomerelia, Prussia and Samogitia.