Profession: Duke of Prussia
Biography: Albert Frederick was the Duke of Prussia, coming to power in 1569 after paying feudal homage to his cousin, Zygmunt August, who was then the King of Poland.
While he technically reigned until 1603, though was noted to have shown signs of mental disorder since 1572. The regency was first controlled in his stead by his cousin George Frederick. Joachim Frederick then served as regent from 1611
Upon Albert Frederick's death in 1618, John Sigismund, the son of Joachim Frederick, was made Duke of Prussia by King Sigismund III Vasa.
- 1569-07-19 Albert Frederick becomes Duke of Prussia