Princess Maria of Greece and Denmark () (; 3 March [O.S. 20 February] 1876 – 14 December 1940) was a daughter of King George I of Greece and his wife Grand Duchess Olga Constantinovna of Russia. She was a sister of King Constantine I of Greece and a first cousin of Tsar Nicholas II of Russia. Born as a princess of Greece and Denmark, she was educated in Athens by private tutors. Her father instilled in her a great love for Greece and throughout her life, she remained a fervent patriot. She married Grand Duke George Mikhailovich of Russia, her first cousin once removed, who courted her for five years. The wedding took place in 1900 in Corfu. The couple settled in St. Petersburg and they had two daughters: Princesses Nina (1901 -1974) and Xenia of Russia (1903 -1965). Grand Duke George Mikhailovich had a house built for her in Crimea and he was a devoted father and husband, but the marriage was unhappy. Princess Maria, known upon her marriage as Grand Duchess Maria Georgievna of Russia, neither got to love her husband nor her adopted country. Longing for her native Greece, she never adapted to life in Russia. Over the years, she became estranged from her husband taking any opportunity to spend time abroad. At the outbreak of World War I, she was vacationing in England with her daughters and chose not to return to Russia. During the conflict, she was a patron of three military hospitals in Harrogate, which she financed generously. Her husband was trapped in Russia after the revolution and he was shot by the Bolsheviks with several other Romanov relatives in January 1919. In her widowhood, deprived of her Russian income, Princess Maria faced serious financial difficulties. She returned to live in Greece with her daughters in 1920. There, she began a relationship with Admiral Perikles Ioannidis, who had been the commander of the ship that she took at her return to Athens. They were married in 1922. The proclamation of the Second Hellenic Republic in 1924, sent her into exile. The princess returned to live in Britain for a couple of years and she settled in Rome in 1926 with her second husband. She lived in Italy for over a decade until the outbreak of the Greco-Italian War in 1940 forced her to return to her native Greece. She was in poor health and