United Duchies of Jülich-Cleves-Berg
His parents were William "the Rich", Duke of Jülich-Cleves-Berg (1516–92) and Maria of Austria (1531–81), a daughter of Ferdinand I, Holy Roman Emperor and Anna of Bohemia and Hungary. He grew up and was educated in Xanten. Johann Wilhelm became Bishop of Münster. However, after the unexpected death of his elder brother Karl Friedrich, Wilhelm was needed to succeed his father as Duke of Jülich-Cleves-Berg, a secular fief. He was also Count of Altena. The United Duchies of Jülich-Cleves-Berg was a combination of "reichsfrei" states within the Holy Roman Empire.