Władysław IV Vasa

Władysław IV Vasa or Ladislaus IV (9 June 1595 – 20 May 1648) was King of Poland, Grand Duke of Lithuania and claimant of the thrones of Sweden and Russia. Born into the House of Vasa as a prince of Poland and of Sweden, Władysław IV was the eldest son of Sigismund III Vasa and Sigismund's first wife, Anna of Austria.

Władysław was elected as the tsar of Russia by the Seven Boyars in 1610, when the Polish army captured Moscow, but did not assume the throne because of his father's position and a popular uprising. Nevertheless, until 1634, he used the titular title of grand duke of Moscow. Following his election as king of Poland and grand duke of Lithuania in 1632, he was largely successful in defending the Polish–Lithuanian Commonwealth against foreign invasion, most notably in the Smolensk War of 1632–1634 in which he participated personally.

He supported religious tolerance and carried out military reforms, such as the founding of the Commonwealth Navy. Władysław was also a renowned patron of the arts and music. He gained fame by defeating the Ottoman Empire, strengthening royal power, and reforming the Commonwealth's political system, although he failed at reclaiming the Swedish throne. Despite that failure, his personal charisma and popularity among all segments of society contributed to relative internal calm in the Commonwealth.

He died without a legitimate son and was succeeded to the Polish-Lithuanian throne by his half-brother, John II Casimir Vasa. Władysław's death marked the end of relative stability in the Polish–Lithuanian Commonwealth, as conflicts and tensions that had been growing over several decades came to a head with devastating consequences. The Khmelnytsky Uprising in the east (1648) and the subsequent Swedish invasion ("the Deluge", 1655–1660) weakened the country and diminished Poland's status as a regional power. For that reason, Władysław's reign was seen in following decades as a bygone golden era of stability and prosperity.