Treaty of Kėdainiai
|Type||Legal status of the Grand Duchy of Lithuania|
|Signed||17 August 1655|
|Signatories||Charles X Gustav of Sweden
Janusz II Radziwiłł
Grand Duchy of Lithuania
The Treaty of Kėdainiai or Kiejdany, signed on 17 August 1655, was a Swedish–Lithuanian agreement during the Second Northern War. After the Polish forces had been decisively defeated in the Battle of Ujście, whereupon the Poznań and Kalisz palatines surrendered to Sweden, Lithuanian hetman Janusz Radziwiłł decided to discontinue the war. In Kėdainiai, 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 On 20 October, the treaty was superseded by the Union of Kėdainiai, which united the Grand Duchy of Lithuania with the Swedish Empire.