[1595–AUGUST 6, 1657]

Seventeenth-century Cossack ruler

Frequently identified by the Polish translation of his name, Bogdan (or Bohdan) Chmielnicki was hetman (supreme head) of the Cossacks based in southcentral Ukraine from 1648 until his death. He is also widely known by the Ukrainian form of his name, Bohdan Khmel'nyts'kyi. During the decade of his rule, Chmielnicki was responsible for leading a successful revolt against the Polish-Lithuanian Commonwealth, which dominated Ukraine at the time, and for bringing the lands he controlled under the authority of the tsardom of Muscovy in 1654.

During the first half of the seventeenth century much of Ukraine was a borderland region of southeastern Poland-Lithuania, beyond which a no-man's land separated it from the Ottoman Empire and its client state, the Crimean Tatar Khanate. Until 1648 Chmielnicki was what is known as a registered Cossack, that is, a kind of...