Sigismund II Jagellon, King of Poland and Grand Duke of Lithuania

SIGISMONDO II Jagellone, King of POLAND and Grand Duke of LITHUANIA. - Son of King Sigismondo I and Bona Sforza, born August 1, 1520 in Kraków, died July 7, 1572 in Knyszyn.

Before his father's death (1548) he had already administered the Grand Duchy of Lithuania and shown interest in the Protestant Reformation; he corresponded with Melanchthon and Calvin, kept Protestant preachers at his court in Vilnius, and maintained cordial relations with the Lutheran sovereigns; but this understanding with the heretics was abruptly broken by the sovereign's secret marriage to Barbara Radziwiłł (1547), which was opposed by the Polish nobility with Protestant tendencies, who demanded its annulment at the Diet of Piotrków in 1548: the Poles feared an increased influence of the Lithuanian nobility on the government. With the support of high dignitaries of the Catholic Church, S. nevertheless succeeded in breaking the opposition and having Barbara crowned on Dec. 7, 1550 in the cathedral of Kraków, and he promised to grant special aid to the Catholic Church, but in reality he tolerated Protestant preachers, including several Italians, spreading the ideas of the Reformation. In foreign policy he maintained good-neighborly relations with the Habsburgs and opposed Russian, Danish, and Swedish attempts to occupy Livonia. With the Treaty of Lublin of July 1, 1569, he replaced the personal union between Poland and Lithuania with a real union, based on the king and the Seym (Diet of Estates). - See pl. XXXVII.