Question: When did Gerhard Vii, Duke Of Jülich-Berg's wife die?
Answer: 9 September 1473

His spouse Sophie of Saxe-Lauenburg then wielded regency for him. Sophie of Saxe-Lauenburg (born: before 1444; died: 9 September 1473) was a German regent, Duchess of Jülich-Berg by marriage to Gerhard VIII of Jülich-Berg, and regent of Jülich, Berg and Ravensberg for her eldest son William IV from 1456 until 1473.