 As a grandchild of Queen Victoria, Wilhelm was a first cousin of the future King George V, as well as of Queens Marie of Romania, Maud of Norway, Victoria Eugenie of Spain, and the Empress Alexandra of Russia.In 1889, Wilhelm's younger sister, Sophia, married the future King Constantine I of Greece.Wilhelm was infuriated by his sister's conversion to Greek Orthodoxy; upon her marriage, he attempted to ban her from entering Germany.