Bohdan Chmielnicki (all: bəkhdän´ khmĕlnēt´skē), c.1595–1657, hetman (leader) of Ukraine. An educated member of the Ukrainian gentry, he early joined the Ukrainian Cossacks. Elected (1648) hetman of the Zaporizhzhya Cossacks, he led their rebellion against oppressive Polish rule. After defeating the Polish army, the Cossacks joined with the Polish peasantry, murdering over 100,000 Jews. At first successful, the revolt grew into a national revolution of the Ukrainian people. Two treaties (1649, 1651) with Poland—the second less satisfactory than the first—were broken by the Poles, and the war dragged on. As compromise with Poland proved to be impossible, Chmielnicki's objective came to be an independent Ukrainian state; for aid he turned to Czar Alexis of Russia. In 1654 at Pereyaslavl (renamed Pereyaslav-Khmelnytskyy in 1944), Ukraine was proclaimed a protectorate of Moscow and recognized as autonomous. The alliance ultimately led to the destruction of Ukrainian autonomy; its immediate result was resumption of the war, which ended only in 1667 with the Treaty of Andrusov, which partitioned Ukraine between Poland and Russia.