Marie Sophie Frédérique Dagmar de Schleswig-Holstein-Sonderbourg-Glucksbourg, Princess of Denmark (1847-1928) was a member of the Danish royal family, who, through her marriage to Tsar Alexander III, became Grand Duchess and later Empress of Russia under the name Marie Fedorovna.
Initially engaged to Grand Duke Nicholas, heir to the Russian throne but who died prematurely, she married his brother, Tsarevich Alexander Alexandrovich, in 1866, after converting to Orthodoxy. In 1881, the assassination of her father-in-law Alexander II made her husband Emperor of Russia and herself Empress. Pretty and popular, she was involved in charity work and Russian social and cultural life.
She left Russia for Denmark in April 1919, thus avoiding the tragic fate of the entire Romanov family the previous year, including her son Emperor Nicholas II.