At the beginning of the Khmelnytsky uprising in the early months of 1648, Polish forces tried to suppress it but suffered two defeats at the battle of Zhovti Vody and Korsun. This was followed by the death of king Władysław IV on 20 May N.S. and Chancellor Jerzy Ossolinski called for a congress of notables in Warsaw on 9 June, at which Zaslawski, Ostrorog and Koniecpolski were designated provisional commanders, and Adam Kisiel was instructed to enter into negotiations with Khmelnytsky. By 27 June, the Bratslav region, Volhynia and the southern Kyiv region were engulfed by the uprising, Khmelnytsky had halted at Bila Tserkva, Tughay Bey foraged with his horde, and the khan had returned to the Crimea with two hundred thousand captives. By August, Kysil's commission had failed and this period of truce was coming to an end.