Truce of Vilna

The Truce of Vilna, Treaty of Wilno or Truce or Treaty of Niemieża was a treaty signed at Niemieża (modern Nemėžis) near Vilnius (also known as Vilna or Wilno) on 3 November 1656 between the Tsardom of Russia and Polish–Lithuanian Commonwealth, introducing a truce during the Russo-Polish War (1654–67) and an anti-Swedish alliance in the contemporaneous Second Northern War. In return for ceasing hostilities and fighting Sweden alongside Poland–Lithuania, the treaty promised tsar Alexis of Russia to succeed the Polish–Lithuanian throne as soon as John II Casimir Vasa would die. Thus began the Russo-Swedish War (1656–1658), which Russia would lose.

The Cossack Hetmanate under Bohdan Khmelnytsky was excluded from the negotiations, and the Truce did nothing to address the Muscovite occupation of Lithuania and the status of Ukraine. The Ukrainian Cossacks were enraged by this Russian betrayal of the 1654 Pereiaslav Agreement that promised Muscovite military support for the Cossacks against the Commonwealth. Without their knowledge or consent, the Russian tsar had suddenly made a separate peace deal with the Commonwealth, and violated his duty of military protection of the Cossacks. Khmelnytsky therefore ignored the Truce of Vilna, and subsequently supported the Transylvanian invasion of Poland on the Swedish side.