Bila Tserkva, Treaty of. A treaty signed on 28 September 1651 between Hetman Bohdan Khmelnytsky and the Polish hetman Mikołaj Potocki. The treaty resulted from the defeat of the Ukrainian Cossack forces and their Tatar allies at Berestechko. The treaty was less advantageous to Ukraine than was the Treaty of Zboriv: the number of registered Cossacks was reduced by half, to 20,000. Only Kyiv voivodeship was to remain autonomous, while Bratslav voivodeship and Chernihiv voivodeship were to come under royal administration again. The Polish magnates and landowners got the right to return to their lands. Khmelnytsky promised to end the alliance with the Crimean khan and to desist from independent relations with foreign powers. The Treaty of Bila Tserkva provided a respite before new preparations for war. In 1652 Khmelnytsky resumed the Cossack-Polish War, thereby annulling the treaty.