Duke Alexander Frederick Constantin of Oldenburg (; , Alexander Petrovich Oldenburgsky; – 6 September 1932) was the second son of Duke Peter of Oldenburg and his wife, Princess Therese of Nassau-Weilburg. Though he had a German title and ancestry, Alexander and his siblings were born and raised in St. Petersburg as the grandchildren of Grand Duchess Catherine Pavlovna of Russia. Alexander served as Adjutant general to Alexander III of Russia, and also as commanding general of the Imperial Guard. Alexander was the Russian candidate submitted to succeed Alexander, Prince of Bulgaria, though this nomination failed to gain the support of the other great European powers. At the outbreak of World War I, Nicholas II of Russia appointed Alexander, a medical doctor, as supreme chief of the medical service of the military and naval forces. Alexander and his wife Princess Eugenia Maximilianovna of Leuchtenberg were noted for their philanthropy, establishing schools, hospitals, orphanages, and other charitable organizations in Russia. During World War I, the duke famously invited wounded British and French soldiers to stay for free in a sanatorium he founded in the Crimea. When the Russian revolution broke out, Alexander was reported to have been one of the Imperial family killed by the newly emerged Bolshevik government, though this turned out to be only a rumor as the duke was able to escape and hide away in Finland and eventually to France, where he died at Biarritz on 6 September 1932. Family and early life Alexander's grandfather had married Grand Duchess Catherine Pavlovna, daughter of Paul I of Russia, and their descendants had been raised in Russia ever since and become completely "Russianized". Thus despite his German title, Duke Alexander, like his father before him, had grown up entirely in Russia, serving his military service for the czars. He was always considered a part of the Russian imperial family. Marriage On 19 January 1868 at the Winter Palace, Alexander married Princess Eugenia Maximilianovna of Leuchtenberg, a daughter of Maximilian de Beauharnais, 3rd Duke of Leuchtenberg. Like his own family, Eugenia was also an offshoot of the Imperial family, as her mother was Grand Duchess Maria Nikolaevna, eldest daughter of Nicholas I of Russia. She was entitled to the rank Imperial Highness, and was born and raised in St. Petersburg. The couple had one son, Peter (21 November 1868 – 11 March 1924). Eugenia had a long-standing friendship with Empress Maria