Nobility. Born the only son of Albrecht von Brandenburg-Ansbach and his second wife Maria von Braunschweig. He succeeded in 1568 as Duke of Prussia. In 1572 he showed first signs of mental disorder and in 1578 Stephan Báthory gave his cousin Georg Friedrich the regency over Prussia.
He was isolated and died completely insane. As he died without a male heir, his son-in-law Johann Sigismund succeeded him as duke.
Albrecht von Brandenburg-Ansbach
Marie Eleonore von Jülich-Kleve-Berg