Princess Elisabeth of Hesse and by Rhine, later Grand Duchess Elizabeth Feodorovna of Russia (Russian: Елизавета Фёдоровна Романова, romanized: Yelizaveta Fyodorovna Romanova, Elizabeth Feodorovna Romanova; canonised as Holy Martyr Elizabeth Feodorovna; 1 November 1864 – 18 July 1918), was a German Hessian and Rhenish princess of the House of Hesse-Darmstadt, and the wife of Grand Duke Sergei Alexandrovich of Russia, the fifth son of Emperor Alexander II of Russia and Princess Marie of Hesse and by Rhine. She was also a maternal great-aunt of Prince Philip, Duke of Edinburgh, the consort of Queen Elizabeth II.