The Treaty of Melno (; ) or Treaty of Lake Melno () was a peace treaty ending the Gollub War. It was signed on 27 September 1422, between the Teutonic Knights and an alliance of the Kingdom of Poland and the Grand Duchy of Lithuania at Lake Melno (; ), east of Graudenz (Grudziądz). The treaty resolved territorial disputes between the Knights and Lithuania regarding Samogitia, which had dragged on since 1382, and determined the Prussian–Lithuanian border, which afterwards remained unchanged for about 500 years. A portion of the original border survives as a portion of the modern border between the Republic of Lithuania and Kaliningrad Oblast, Russia, making it one of the oldest and most stable borders in Europe. Background The First Peace of Thorn of 1411 did not resolve long-standing territorial disputes between the Teutonic Knights and the Polish–Lithuanian union. The peace transferred Samogitia to the Grand Duchy of Lithuania, but only for the lifetimes of Polish King Jogaila (Władysław II Jagiełło) and Lithuanian Grand Duke Vytautas. At the time both rulers were aged men. Soon disagreements arose as to the Samogitian borders: Vytautas claimed that the entire northern bank of the Neman River, including the port of Memel (Klaipėda), was Samogitian territory. The dispute was mediated at the Council of Constance and by Sigismund, Holy Roman Emperor. When Sigismund delivered an unfavorable judgment to the Lithuanians, Jogaila and Vytautas invaded the monastic state of the Teutonic Knights in July 1422, starting the Gollub War. The Teutonic Knights, led by Grand Master Paul von Rusdorf, were unable to mount a suitable defense. However Poland–Lithuania decided to end the conflict before reinforcements from the Holy Roman Empire could arrive through Farther Pomerania. A truce was signed on 17 September 1422. Each side named eight representatives, gave them full authority to negotiate, and sent them to the Polish Army camp near Lake Melno. The Treaty of Melno was concluded ten days later, on 27 September. Provisions According to the terms of the treaty, the Teutonic Knights for the first time renounced all territorial, political, and missionary claims against the Grand Duchy of Lithuania. Samogitia was permanently ceded to Lithuania. The Prussian–Lithuanian border ran from sparsely inhabited wilderness in Suvalkija, through the triangle north of the Neman River, to Nemirseta on the Baltic Sea. Thus the Knights still controlled Neman's lower reaches and Memel (Klaipėda), an important seaport and trade center.