John Casimir II Vasa of Poland, or Polish: Jan II Kazimierz Waza, (March 22, 1609 - December 6, 1672), King of the Polish-Lithuanian Commonwealth, and Duke of Opole in Silesia. His parents were Sigismund III of Poland (1566-1632), and Constance of Austria Habsburg (1588-1631). John Casimir was thus the nephew of Ferdinand II, Holy Roman Emperor.

Royal titles

• Official titles in Latin: Ioannes Casimirus, Dei Gratia rex Poloniae, magnus dux Lithuaniae, Russie, Prussiae, Masoviae, Samogitiae, Livoniae, Smolenscie, Severiae, Czernichoviaeque; nec non Suecorum, Gothorum, Vandalorumque haereditarius rex, etc.

• English translation: John Casimir, by God's grace King of Poland, Grand Duke of Lithuania, Ruthenia, Prussia, Masovia, Samogitia, Livonia, Smolensk, Siewierz and, Czernichow; and also hereditary King of the Swedes, Goths and Vandals.

Biography

His father Sigismund, grandson of Gustav I of Sweden, had succeded his father to the Swedish throne in 1592 only to be deposed from the by his uncle Charles IX of Sweden in 1599. This lead to a long standing feud where the Polish kings of the house of Vasa claimed the Swedish throne. Effects of this were the Swedish War (1600-1629). Poland and Sweden were also on opposite sides in the Thirty Years' War (1618-1648).

In 1648 John Casimir II succeeded his half brother and cousin on the Polish throne. The reign of the last of Vasas in the Commonwealth would be dominated by the culumination in the war with Sweden (The Deluge), groundwork for which was laid down by the two previous Vasa kings of the Commonwealth.

In 1660 he would be forced to renounce his claims to the Swedish throne and acknowledge Swedish sovereignty over Livonia and city of Riga. John abdicated on September 16, 1668 and returned to France where he joined the Jesuit order and became an ordinary monk. He died in 1672.