Registered Cossacks
Eventually the forces of the Crown of Poland under Mikołaj Potocki entered Ukraine and joined with the Registered Cossacks. On 16 December 1637 the combined force attacked the Cossacks at Kumeyki near Cherkassy, in what became known as the battle of Kumeyki. Inexperienced Cossacks overextended their wagon fort and their lines were easily pierced by experienced soldiers such as Samuel Łaszcz. The battle, while disastrous for the Registered Cossacks who were killed almost to the last man, was victorious for the Polish side and the Cossacks retreated in disarray, while Pavlyuk was captured.