When Russia invaded Ukraine in February 2022, Poland stepped forward as one of its eastern neighbor’s staunchest supporters. But the ongoing eruption involving Russia, Ukraine and Poland is just the latest tragic chapter in a three-way strategic power struggle that has been running hot and cold for nearly 500 years. Relative if temporary peace descended over Western Europe with the end of the Thirty Years’ War in 1648. But that same year the flames of war raged throughout Eastern Europe.
The citizens of present-day Ukraine, Poland and Russia have long historical memories. Among the most searing episodes in their collective past is the Khmelnytsky Uprising of 1648–57, also known as the Cossack–Polish War. During that conflict Ukraine, supported by tsarist Russia, broke free from nearly a century of domination by the Polish-Lithuanian Commonwealth. The Crimean Tatars initially supported the Cossacks, only to switch sides twice during the conflict. Before the uprising concluded, Poland found itself engulfed in two additional wars: The Russo-Polish War of 1654–67 and the Swedish invasion that triggered the Second Northern War of 1655–60. The combination of the three wars led to the emergence of the Ukrainian Cossack hetmanate under Russian protection, the territorial and political expansion of tsarist Russia, and the beginning of the long decline of the Polish-Lithuanian Commonwealth.
most of what today is Ukraine lay within a region known as Ruthenia. Much of Ruthenia at the time was under the control of either the Kingdom of Poland or the Grand Duchy of Lithuania. The 1569 Union of Lublin linked Poland and Lithuania as a commonwealth, which consolidated control over Ruthenia. In 1572 Eastern Slavs known as Registered Cossacks became a standing formation of the commonwealth’s army, eventually totaling 40,000 troops in 16 regiments. While many of the elite Ruthenian noblemen, among them Prince Jeremi Wisniowiecki, readily assimilated into Polish culture
