He was the oldest child and oldest son of Emperor William II and Empress Augusta Victoria, née Princess of Schleswig-Holstein. He became German Emperor and King of Prussia upon the death of his father 4 June 1941. Emperor William III married 6 June 1905 in Berlin to Duchess Cecilia of Mecklenburg-Schwerin (1886-1954), a daughter of Grand Duke Frederick Francis III of Mecklenburg-Schwerin and his wife, Grand Duchess Anastasia Mikhailovna, née Grand Duchess of Russia. William and Cecilia had the following issue: William (1906-1940) Hubertus (1909-1950) Frederick (1911-1966) Alexandrina (1915-1980)