Sigismund I of Poland (; ) (1 January 1467 – 1 April 1548), of the Jagiellon dynasty, reigned as King of Poland and also as the Grand Duke of Lithuania from 1506 until 1548. Earlier, Sigismund had been invested as Duke of Silesia. A successful monarch and a great patron of arts, he established Polish suzerainty over Ducal Prussia (East Prussia) and incorporated the duchy of Mazovia into the Polish state, securing the nation's wealth, culture and power.