William III (Frederick William Victor Augustus Ernest, German: Friedrich Wilhelm Victor August Ernst) was German Emperor and King of Prussia. He was born 6 May 1882 in the Marmorpalais, Potsdam, Brandenburg, German Empire, and died in the same place 20 July 1951.
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:
Louis Ferdinand (1907-1994), who succeeded his father as Emperor Louis Ferdinand I
The surviving descendants are (through ancestry on Emperor William's side) in the Line of British Succession and (through ancestry on Empress Cecilia's side) in the Line of Succession to the Swedish Throne.