Northern War of 1655–1660

Northern War of 1655–1660
Part of the Northern Wars

From left to right:
DateJune 1655 – 23 April 1660
Location
Result See § Peace
Territorial
changes
Belligerents
Swedish Empire
Brandenburg-Prussia (1656–57)
Transylvania
Swedish Lithuania
Polish–Lithuanian Commonwealth
Denmark–Norway (from 1657)
Habsburg Monarchy
Russia (1656–58)
Brandenburg-Prussia (1655–56, 1657–60)
Crimean Khanate
Commanders and leaders
Charles X Gustav
Arvid Wittenberg 
Magnus de la Gardie
Johan Risingh 
Janusz Radziwiłł 
Bogusław Radziwiłł 
Frederick William I
George II 
John II Casimir
Stefan Czarniecki
Paweł Jan Sapieha
Wincenty Korwin Gosiewski
Frederick III
Alexis of Russia
Frederick William I
Peter Stuyvesant
Strength
55–70,000 (average strength, 1655–1660) Unknown
Casualties and losses
70,000 dead (excluding mercenaries) Unknown

The Northern War of 1655–1660 was fought between Sweden and the Polish–Lithuanian Commonwealth, with participation at different times by Russia, Brandenburg-Prussia, the Habsburg monarchy, and Denmark–Norway. It ended with the treaties of Copenhagen and Oliva in 1660.

In 1655, Charles X took advantage of the Russo-Polish War (1654–67) to over-run western Poland. The Grand Duchy of Lithuania was annexed by Sweden, and John II Casimir Vasa took refuge in Vienna. He managed to regain parts of his kingdom in 1656, and the conflict widened when Russia declared war on Sweden, supported by Emperor Leopold and Frederick III of Denmark.

Previously allied with Sweden, Brandenburg switched sides in 1657 when Casimir granted Frederick William I sovereignty over the Duchy of Prussia. That winter, Charles X invaded Denmark and forced Frederick to withdraw from Southern Sweden. However, a second Swedish offensive failed, and by 1659 the war had become one of attrition, with neither side able to gain a decisive advantage.

After Charles died in February 1660, his son made peace with his opponents. Sweden kept most of its gains from Denmark, but the belligerents largely returned to the status quo ante bellum.