First ruler of the Polish-Lithuanian Commonwealth (1569-72)
Sigismund II Augustus (Polish: Zygmunt II August, Lithuanian: Žygimantas Augustas; 1 August 1520 – 7 July 1572) was King of Poland and Grand Duke of Lithuania, the son of Sigismund I the Old, whom Sigismund II succeeded in 1548. He was the first ruler of the Polish–Lithuanian Commonwealth and the last male monarch from the Jagiellonian dynasty. Sigismund was elder of two sons of Italian-born Bona Sforza and Sigismund the Old, and the only one to survive infancy. From the beginning he was groomed and extensively educated as a successor.
https://en.wikipedia.org/wiki/Sigismund_II_Augustus
Sigismund II Augustus (Polish: Zygmunt II August, Lithuanian: Žygimantas Augustas; 1 August 1520 – 7 July 1572) was King of Poland and Grand Duke of Lithuania, the son of Sigismund I the Old, whom Sigismund II succeeded in 1548. He was the first ruler of the Polish–Lithuanian Commonwealth and the last male monarch from the Jagiellonian dynasty. Sigismund was elder of two sons of Italian-born Bona Sforza and Sigismund the Old, and the only one to survive infancy. From the beginning he was groomed and extensively educated as a successor.
