Albert of Prussia was a notable figure in the 16th century, born in 1490. He was the last Grand Master of the Teutonic Knights and played a significant role in the transition of the order from a religious to a secular state. In 1525, he converted to Lutheranism and established the Duchy of Prussia, becoming its first duke. His reign marked the beginning of the Duchy of Prussia as a vassal state of the Kingdom of Poland. Albert's leadership helped to shape the political landscape of northern Europe during the Reformation, influencing both religious and territorial changes in the region.