The Treaty of Zboriv was signed on August 17, 1649, after the Battle of Zboriv when the Crown forces of about 25,000 led by king John II Casimir of Poland clashed against a combined force of Ukrainian Cossacks and Crimean Tatars, led by hetman Bohdan Khmelnytsky and khan İslâm III Giray of Crimea respectively, which numbered about 80,000.
According to the concluded agreement the number of Registered Cossacks increased up to 40 thousand, the Polish army and Jews were banned from the territory of the Kiev Voivodeship, Bratslav Voivodeship, and Chernihiv Voivodeship, governmental offices in the Cossack Hetmanate could be held only by Cossack leaders, the Orthodox Church was granted privileges, and the Crimean Khanate was to be paid a large sum of money.
The treaty was ratified by the Diet, which was in session between November 1649 and January 1650, but hostilities resumed when Catholic bishops refused to recognise the provisions of the treaty (i.e. admission to the Senate of Orthodox metropolitan of Kiev, Sylvestr Kosiv).