Union of Kėdainiai
Text of the treaty in Latin | |
| Type | Establishing a Swedish–Lithuanian Union and legally dissolving the Polish–Lithuanian Commonwealth |
|---|---|
| Signed | 20 October 1655 |
| Location | Kėdainiai, Lithuania |
| Signatories | |
| Parties | |
The Union of Kėdainiai or Agreement of Kėdainiai (Lithuanian: Kėdainių unija, Swedish: Kėdainiai förbund) was an agreement between magnates of the Grand Duchy of Lithuania and the king of the Swedish Empire, Charles X Gustav, that was signed on 20 October 1655, during the Swedish Deluge of the Second Northern War. In contrast to the Treaty of Kėdainiai of 17 August, which put Lithuania under Swedish protection, the Swedish–Lithuanian union's purpose was to end the Lithuanian union with Poland and to set up the Grand Duchy of Lithuania as a protectorate under the Swedish Crown with some of the estates being ruled by the Radziwiłł (Radvila) family.
The agreement was short-lived since the Swedish defeat at the Battles of Warka and Prostki and an uprising organised by the pro-Commonwealth nobility in Poland and Lithuania put an end to Swedish power and to the Radziwiłłs' influence.