This rare photograph of nine monarchs gathered in one room was taken by W. & D. Downey on May 20, 1910. The sovereigns posed for a portrait within Windsor Castle while attending the funeral of King Edward VII.  Never again would so much European royalty be assembled in one place, or even exist. Just four years later, some of these men would be mortal enemies.

Standing, from left to right: King Haakon VII of Norway, Tsar Ferdinand of Bulgaria, King Manuel II of Portugal, Kaiser Wilhelm II of the German Empire, King George I of Greece and King Albert I of Belgium.

Seated, from left to right: King Alfonso XIII of Spain, King-Emperor George V of the United Kingdom and King Frederick VIII of Denmark.