The Treaty of Kėdainiai or Kiejdany, signed on 17 August 1655, was a Swedish

Swedish Empire

The Swedish Empire refers to the Kingdom of Sweden between 1561 and 1721 . During this time, Sweden was one of the great European powers. In Swedish, the period is called Stormaktstiden, literally meaning "the Great Power Era"...

–Lithuanian

Grand Duchy of Lithuania

The Grand Duchy of Lithuania was a European state from the 12th /13th century until 1569 and then as a constituent part of Polish-Lithuanian Commonwealth until 1791 when Constitution of May 3, 1791 abolished it in favor of unitary state. It was founded by the Lithuanians, one of the polytheistic...

 agreement during the Second Northern War

Second Northern War

The Second Northern War was fought between Sweden and its adversaries the Polish–Lithuanian Commonwealth , Russia , Brandenburg-Prussia , the Habsburg Monarchy and Denmark–Norway...

. After the Polish forces had been decisively defeated in the Battle of Ujście

Battle of Ujscie

The Battle of Ujście was fought on July 24-July 25, 1655 between forces of the Polish-Lithuanian Commonwealth commanded by Krzysztof Opaliński and Andrzej Grudziński on one side, and on the other Swedish forces commanded by Arvid Wittenberg...

, whereupon the Poznan

Poznan

Poznań is a city on the Warta river in west-central Poland, with a population of 556,022 in June 2009. It is among the oldest cities in Poland, and was one of the most important centres in the early Polish state, whose first rulers were buried at Poznań's cathedral. It is sometimes claimed to be...

 and Kalisz

Kalisz

Kalisz is a city in central Poland with 106,857 inhabitants , the capital city of the Kalisz Region. Situated on the Prosna river in the southeastern part of the Greater Poland Voivodeship, the city forms a conurbation with the nearby towns of Ostrów Wielkopolski and Nowe Skalmierzyce...

 palatines surrendered to Sweden, Lithuanian hetman

Hetman

Hetman was the title of the second-highest military commander in 15th- to 18th-century Poland and the Grand Duchy of Lithuania, which together, from 1569 to 1795, comprised the Polish-Lithuanian Commonwealth, or Rzeczpospolita....

 Janusz Radziwiłł decided to discontinue the war. In Kėdainiai

Kedainiai

Kėdainiai is one of the oldest cities in Lithuania. It is located on the Nevėžis River. First mentioned in the 1372 Livonian Chronicle of Hermann de Wartberge, its population as of 2008 was 30,214. Its old town dates to the 17th century....

, he accepted Swedish protection. The treaty further specified that the Polish–Lithuanian Commonwealth was not dissolved and Lithuanian forces would not fight Polish forces, although the text of the treaty included protests against the lack of Polish support. On 20 October, the treaty was superseded by the Union of Kėdainiai

Union of Kedainiai

Union of Kėdainiai was an agreement between several magnates of the Grand Duchy of Lithuania and the king of the Swedish Empire, Charles X Gustav. It was signed on 20 October 1655 during the "Swedish Deluge", part of the Second Northern War...

, which united the Grand Duchy of Lithuania

Grand Duchy of Lithuania

The Grand Duchy of Lithuania was a European state from the 12th /13th century until 1569 and then as a constituent part of Polish-Lithuanian Commonwealth until 1791 when Constitution of May 3, 1791 abolished it in favor of unitary state. It was founded by the Lithuanians, one of the polytheistic...

 with the Swedish Empire

Swedish Empire

The Swedish Empire refers to the Kingdom of Sweden between 1561 and 1721 . During this time, Sweden was one of the great European powers. In Swedish, the period is called Stormaktstiden, literally meaning "the Great Power Era"...

.