SIGISMONDO III Vasa, king of POLAND and SWEDEN. — Son of Giovanni III, king of Sweden, and of Caterina Jagellonica, born on 20 June 1566 at Gripsholm (Sweden), died on 30 April 1632 at Warsaw.
He was elected king of Poland in August. Upon his father’s death, in 1592, he succeeded in having himself crowned king of Sweden as well, giving an undertaking to respect the decisions of the Synod of Uppsala of 1593, which introduced the articles of the Augsburg Confession into Sweden. S., who instead was a firm and convinced supporter of the Catholic Reformation in the Nordic countries, soon found himself in conflict with his subjects on the other side of the Baltic. After unsuccessfully attempting to conquer Sweden with an army in 1598, he was declared deposed from the throne the following year. All of S.’s subsequent foreign policy was aimed at recovering the Swedish crown, but every effort proved fruitless. Especially after the accession of Gustavo Adolfo, S. not only lost all hope of returning to his father’s throne, but Poland itself, drawn into this dynastic struggle, suffered the consequences: the Peace of Altmark (1629), through the acquisition of Livonia, in fact secured Sweden’s predominance in the Baltic. Throughout his reign, S. was a sincere, active, and resolute supporter of the Catholic faith. The loss of the Swedish crown on the one hand, and the political opposition of the Protestants within Poland itself on the other, strengthened his resolve to promote the Counter-Reformation by every means and to grant every kind of support to the Jesuits.