The destruction of the Golden Horde in the 15th Century by the Timurid Empire virtually swept from the map the last remnants of the Mongols’ conquest of northeastern Europe. All that remained was the Tartar Khanate of Crimea and a vast and deserted steppe that stretched from the Carpathian Mountains in the west to the Urals in the east. Into this void stepped two powerful kingdoms, the Polish Lithuanian Commonwealth and the Russian Kingdom of Muscovy.

Where the frontiers of the two states met opposite the Crimean Tartars along the river basins of the Dnieper, Don, and Donetz, the Poles and Russians encouraged settlers to the area to provide a bulwark against the slaving raids of the Muslim Tartars and Ottoman Turks. The settlers were not an ethnic group but fiercely independent homesteaders, frontiersmen, and adventurers known as Cossacks. The Cossacks formed “Sichs” (literally “cuts”, either of land or the logs that formed their stockades and forts) and were expected to defend the area in exchange for land and fealty.

By the 17th century, the Zaporizhian Sich along the Dnieper River was a semi-autonomous part of the powerful Polish Lithuanian Commonwealth. However, the Orthodox Cossacks begrudged their Catholic Polish and Ruthenian (Russified Lithuanians) overlords, then at the vanguard of the Counter-Reformation. Additionally, they despised the increasing number of Poles, Ruthenians, and especially Jews who were settling the Sich. The Cossacks felt that the Szlachta, the pervasive nobility of the Commonwealth, and the Jews, which unlike the rest of Europe were welcomed in the Commonwealth, had more rights than the Cossacks (They were correct). Finally, the Cossacks resented the Polonization of their own quasi-nobility, particularly those that converted to Catholicism. Whenever the situation demanded or the Cossacks showed signs of rebellion, the Polish king usually declared a war against their Muslim neighbors. The war kept the Cossacks busy, and the loot kept them appeased. The Cossacks loved the king because he showered them with privileges as a counterbalance against the nobility.

In 1647, King Wladyslaw IV Vasa, the Swedish king of the Commonwealth (the Commonwealth elected its king, usually a foreigner to keep him weak; it’s complicated) ordered the Cossacks to prepare for a new war against the Ottomans. However, the Sejm (the parliament of nobles) vetoed the idea and ordered the Cossacks to prepare for a new war against the growing power of Muscovy’s successor, the Tsardom of Russia. This sent the Cossacks into a rage. The Russians were coreligionists and used Cossacks themselves. More importantly, those Russians on the Steppe were poor and the Ottomans were rich. Moreover, piracy on the Black Sea, contemporary pirates in the Caribbean had nothing on Cossacks in the Black Sea, was infinitely more lucrative and enjoyable than marching around the cold and endless Steppe. The Cossacks were on the edge of revolt, they just needed a leader.

Enter Bohdan Khmelnitskiy, a respected Ruthenian noblemen and veteran of nearly countless wars against the Ottomans and Crimeans. In 1645, Khmelnitskiy had a land dispute with a powerful Polish magnate (the upper tier of the Szlachta). The magnate’s starost (like a county commissioner) Daniel Czaplinski raided and seized Khmelnitskiy’s land. Khmelnitskiy protested to the king, but the king couldn’t take on such a powerful magnate. So Khmelnitskiy stole Czaplinski’s wife and was arrested. In late 1647, he escaped and fled to the Zaporizhian Sich with his Registered Cossack regiment. (A “Registered Cossack” was a Cossack that was officially in the pay of the king or a magnate.) With the Sich on the brink of rebellion, the charismatic Khmelnitskiy pushed them over. On 25 January, 1648, Khmelnitskiy had the Commonwealth’s administration in the Sich killed. The next day, Bohdan Khmelnitskiy was elected Hetman (warlord) of the Zaporizhian Sich.

Cossack rebellions had been attempted before, but were always crushed by superior heavily armoured Polish cavalry. Unlike in Napoleonic times when Cossacks were known for their superior light cavalry, in the 17th century they constituted the light infantry par excellence. They were akin to tens of thousands of Robert’s Rangers roaming the Steppe. The Poles and Ruthenians always provided the cavalry. So when the Cossacks did revolt, they were always crushed by a massive charge of Husaria and Panzerini, against which they could not hope to stand. In a tribute to Khmelnitskiy’s charisma, he convinced the Sich to make an alliance with their archenemy, the Crimean Tartars, who could provide the cavalry necessary to defeat the Commonwealth. The Crimean Khan dispatched his best general, Tugur Bey, with 18,000 Tartar horsemen to assist the uprising.

Khmelnitskiy’s Uprising would bring fire and sword to the Steppe, and eventually to the Commonwealth itself. Hundreds of thousands of Ruthenian, Polish, Jewish, and Cossack peasants, burghers, and nobles were killed, or sold into slavery to pay for Tugur Bey’s cavalry. Sensing Commonwealth weakness, by 1655 all of its neighbors, Russia, Prussia, Austria, Sweden, and the Ottoman Empire invaded in what is now known in Polish history as “The Deluge”. In 1654, Khmelnitskiy ceded the Zaporizhian Sich to Russia in the Treaty of Pereyaslav for continued military support against the Commonwealth.