The Deluge

The Deluge was a series of devastating mid-seventeenth-century invasions of the Polish-Lithuanian Commonwealth by Sweden, Russia, Transylvania, Brandenburg and the Cossack Hetmanate, traditionally dated from the Khmelnytsky Uprising of 1648 through the Truce of Andrusovo with Russia in 1667, though the name most specifically denotes the Swedish invasion of 1655 to 1660. Weakened by the Cossack revolt in its eastern territories, the Commonwealth was invaded by Sweden under Charles X Gustav in 1655 in a campaign so overwhelming that within months Swedish forces had occupied nearly the entire country, an event that gave the whole period its name. A Polish national resistance eventually reversed the Swedish occupation, aided by the 1656 Treaty of Wehlau realigning Brandenburg-Prussia, but the Commonwealth never fully recovered, having lost roughly a third of its population and vast territory, including eastern lands ceded to Russia. The Deluge is widely regarded by historians as the end of Poland-Lithuania's status as a European great power.