Sigismund II Augustus was the last king of the Jagiellonian Dynasty and ruled as the Grand Duke of Lithuania and King of Poland from 1548 until his death in 1572. He is known for his efforts to strengthen the Polish-Lithuanian Commonwealth and for promoting the arts and culture during the Renaissance period. Sigismund II Augustus was also notable for his attempts to unify Poland and Lithuania through the Union of Lublin in 1569, which created a more centralized state. His reign faced challenges, including conflicts with the Teutonic Knights and internal political struggles, but he left a lasting legacy in Polish history.