Sigismund III Vasa (Polish: Zygmunt III Waza, Swedish: Sigismund, Lithuanian: Žygimantas Vaza; 20 June 1566 – 30 April 1632 N.S.), also known as Sigismund III of Poland, was King of Poland, Grand Duke of Lithuania and monarch of the united Polish–Lithuanian Commonwealth from 1587 to 1632 as well as King of Sweden and Grand Duke of Finland from 1592 until his deposition in 1599.
Sigismund was the son of John III of Sweden and his first wife, Catherine Jagiellon of Poland. Elected to the throne of the Polish–Lithuanian Commonwealth, he sought to create a personal union between the Commonwealth and Sweden (Polish–Swedish union), and succeeded for a time in 1592. After he had been deposed in 1599 from the Swedish throne by his Protestant uncle, Charles IX of Sweden, and a meeting of the Riksens ständer, he spent much of the rest of his life attempting to reclaim it.
A pious yet erratic ruler, Sigismund attempted to hold absolute power in all his dominions. Shortly after his victory over internal opposition, Sigismund took advantage of a period of civil unrest in Muscovy, known as the Time of Troubles, and invaded Russia, holding Moscow for two years (1610–12) and Smolensk thereafter. In 1617 the Polish–Swedish conflict, which had been interrupted by an armistice in 1611, broke out again. While Sigismund's army was also fighting Ottoman forces in Moldavia (1617–21), King Gustavus II Adolphus of Sweden invaded Sigismund's lands, capturing Riga in 1621 and seizing almost all of Polish Livonia. Sigismund, who concluded the Truce of Altmark with Sweden in 1629, never regained the Swedish crown. His Swedish wars resulted, moreover, in Poland's loss of northern Livonian territories and in a diminution of the kingdom's international prestige.
Sigismund remains a highly controversial figure in Poland. One of the country's most recognizable monarchs, he transferred the capital from Kraków to Warsaw in 1596 and his long reign coincided with the apex of the Polish–Lithuanian Commonwealth's prestige, power and economic influence. On the other hand, it was during his reign that the symptoms of decline leading to the Commonwealth's eventual demise surfaced. Popular histories, such as the books of Paweł Jasienica, tend to present Sigismund as the principal source of these destructive processes; whereas academic histories are usually not as damning of him. However, the question of whether the Commonwealth's decline was caused by Sigismund's decisions or had its roots in historical processes beyond his personal control remains highly debatable.
He was commemorated in Warsaw with Sigismund's Column, one of the city's landmarks and the first secular monument in the form of a column in modern history. It was commissioned after Sigismund's death by his son and successor, Władysław IV.