The Deluge: Khmelnytsky Uprising: The Battle of Berestechko ends with a Polish victory.

The Deluge was a series of mid-17th-century military campaigns in the Polish–Lithuanian Commonwealth. In a wider sense, it applies to the period between the Khmelnytsky Uprising of 1648 and the Truce of Andrusovo in 1667, comprising the Polish theatres of the Russo-Polish and Second Northern Wars. In a stricter sense, the term refers to the Swedish invasion and occupation of the Commonwealth as a theatre of the Second Northern War (1655–1660) only; in Poland and Lithuania this period is called the Swedish Deluge, or less commonly the Russo–Swedish Deluge due to the simultaneous Russo-Polish War. The term "deluge" was popularized by Henryk Sienkiewicz in his novel The Deluge (1886).

The Khmelnytsky Uprising, also known as the Cossack–Polish War, Khmelnytsky insurrection, or the National Liberation War, was a Cossack rebellion that took place between 1648 and 1657 in the eastern territories of the Polish–Lithuanian Commonwealth, which led to the creation of a Cossack Hetmanate in Ukraine. Under the command of hetman Bohdan Khmelnytsky, the Zaporozhian Cossacks, allied with the Crimean Tatars and local Ukrainian peasantry, fought against Commonwealth's forces. The insurgency was accompanied by mass atrocities committed by Cossacks against prisoners of war and the civilian population, especially Poles, Jews, Roman Catholic and Ruthenian Uniate clergy, as well as savage reprisals by loyalist Jeremi Wiśniowiecki, the voivode of Ruthenian descent of the Ruthenian Voivodeship.

The Battle of Berestechko was fought between the Cossack Hetmanate and Crimean Khanate against the Polish–Lithuanian Commonwealth as a part of the Khmelnytsky Uprising. Near the site of the present-day city of Berestechko in Ukraine forces of the Zaporozhian Cossacks and Crimean Tatars under the command of Hetman Bohdan Khmelnytsky, Otaman Tymofiy Khmelnytsky, Colonels Ivan Bohun and Fylon Dzhalaliy with Khan İslâm III Giray and Tugay Bey, who was killed in the battle, were defeated by the Polish–Lithuanian Commonwealth's forces under the command of the Polish King John II Casimir, Prince Jeremi Wiśniowiecki, Hetmans Marcin Kalinowski and Stanisław Lanckoroński. The battle took place in the Volhynian Voivodeship on a hilly plain south of the Styr River. The Polish–Lithuanian camp was on the Styr River opposite Berestechko and faced south, towards the Zaporozhian Cossack positions about two kilometers away, with the right flank of the latter covered by the Pliashivka (Pliashova) River and the left flank by Crimean Tatars. It is considered to have been among the largest European land battles of the 17th century.