Treaty of Melno The Treaty of Melno ( ; ) or Treaty of Lake Melno ( ) was a peace treaty ending the Gollub War . It was signed on September 27 , 1422 , between the Teutonic Knights and an alliance of the Kingdom of Poland and the Grand Duchy of Lithuania at Lake Melno ( German : " Melnosee " , " Meldensee " ; Polish : " Jezioro Mełno " ) , 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 partially survives as the border between the Republic of Lithuania and Kaliningrad Oblast , Russia , making it one of the most stable national 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 September 17 , 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 September 27 . 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 . Lithuania retained access to the Baltic Sea between the towns of Palanga ( Polangen ) and Šventoji ( Heiligen Aa ) – a distance of about . However , Lithuania failed to develop harbors in Palanga or Šventoji as there were stiff competition with the nearby established ports Memel and Libau ( Liepāja ) and unfavorable natural conditions . Thus it could not be considered a real access to the sea . For the Knights this short coastline strip was a major sacrifice as it separated the Teutonic Knights in Prussia from their branch in Livonia . The treaty is often described as a mutual Prussian – Lithuanian compromise . The Kingdom of Poland received Nieszawa and half of the Vistula channel from the mouth of the Drwęca River ; in return Poland renounced any territorial claims to Pomerelia , Culmerland , and the Michelauer Land . These results were described as a " disappointment " for Poland . At the time of the treaty , the parties did not have their official seals and therefore it was not immediately ratified . Grand Master Rusdorf attempted to exploit the recess and renegotiate the treaty because his subjects were not satisfied with the terms . He hoped to wage a war with assistance from the Holy Roman Emperor . However , Sigismund and Jogaila met in Käsmark ( Kežmarok ) and agreed to an alliance : Sigismund would end his support to the Knights and Poland – Lithuania would stop their assistance to the Hussites in the Hussite Wars . This meant that Vytautas had to abandon his interventions in Bohemia . The agreement was signed on March 30 , 1423 . The Treaty of Melno was subsequently ratified on May 9 – 18 in Veliuona and approved by Pope Martin V on July 10 , 1423 . Poland – Lithuania affixed some 120 official seals to the treaty . The first Lithuanian signatories were voivode of Vilnius Albertas Manvydas , starosta of Vilnius Kristinas Astikas , voivode of Trakai Jonas Jaunius , elder of Samogitia Mykolas Skirgaila . Aftermath . The treaty effectively ended warfare between the Teutonic Knights and the Grand Duchy of Lithuania , which had continued with brief interruptions since the 13th century . The last volunteer crusaders arrived in October 1422 ; after that the Knights had to rely on their own men or on mercenaries . It was a welcome development to Lithuania , as the treaty allowed it to direct its attention towards its Eastern territories and to internal reforms . War - devastated border regions in Samogitia and Suvalkija began to recover . However , the Polish – Teutonic disputes were not resolved . In a telling episode shortly after the treaty had been signed , the Knights and the Poles disputed a watermill in Lubicz , a strategic post that had been turned into a fortress . Vytautas was angered by the dispute and threatened to give up Palanga to the Knights if Poland did not surrender its claims to Lubicz . The Knights won this dispute . The treaty put an effective end to the Polish – Lithuanian cooperation against the Knights . The Teutonic Knights attempted to befriend the Lithuanians , offering a royal crown to Vytautas in hopes of breaking up the Polish – Lithuanian union . During the Lithuanian Civil War ( 1431 – 1435 ) , Lithuanian Duke Švitrigaila was able to employ the Polish – Teutonic animosity for his own advantages – the Knights invaded Poland , starting the Polish – Teutonic War . The two states battled again during the Thirteen Years ' War ( 1454 – 66 ) , a civil war that tore Prussia in half . The agreement drew the Prussian – Lithuanian border roughly and imprecisely , resulting in local demarcation disputes . The border was redrawn with greater detail and precision in 1532 and 1545 . The border survived without major changes until World War I . In 1919 , the Treaty of Versailles detached the Klaipėda Region ( Memel Territory ) from Germany as a League of Nations mandate . Lithuania annexed the region in 1923 . The southern portion of the border , with small modifications , still survives as the border between Lithuania and Kaliningrad Oblast , Russia .