was buried in the royal cemetery at Tatoi Palace. George and Olga's eldest son, Constantine, became king and his wife, Sophia of Prussia, became the new queen consort. Olga, as queen dowager, was given the use of a wing in the royal palace but soon returned to her native Russia, to spend time with her younger brother, Grand Duke Constantine Constantinovich and his family at his home, and Olga's birthplace, Pavlovsk Palace. World War I In August 1914, Olga was in Russia at the outbreak of World War I, in which the Allied or Entente Powers including Russia, Britain and France fought against the Central Powers including Germany, Austria-Hungary and the Ottoman Empire. She decided to stay in Saint Petersburg and establish a military hospital to support the Russian war effort. Olga created a clinic at Pavlovsk Palace where she cared for wounded soldiers with her sister-in-law, Grand Duchess Elizabeth Mavrikievna. Other members of the imperial family, such as Princess Helen and Olga's granddaughter Grand Duchess Maria Pavlovna founded field hospitals at the front. As the war continued, Olga became aware of the growing crisis in Russia, and attempted to warn Tsarina Alexandra in 1916 of the danger of revolution but the Russian empress refused to listen. A few weeks later, Olga attracted the fury of the Tsarina after signing a petition asking for a pardon for her grandson, Grand Duke Dmitri Pavlovich, who had been exiled to the Persian front for his involvement in the assassination of Alexandra's favorite mystic, Grigori Rasputin. In contrast to Olga, her eldest son, King Constantine I of Greece, was determined to follow a policy of neutrality. His maternal relations were Russian, and his wife was the sister of Kaiser Wilhelm II of Germany. His policy brought him into conflict with Prime Minister Eleftherios Venizelos, who favored the Allies. Constantine was soon accused of being a Germanophile and the Athenian government was regarded with suspicion in London and Paris. In what became known as the National Schism, Venizelos established a parallel government in Thessaloniki in opposition to Constantine. On the collapse of the Tsarist regime in February 1917, Olga's sister-in-law left Pavlovsk with her family, but Olga stayed, soon to be almost alone except for a single young domestic named Anna Egorova. (After the Revolution, Egorova entered the service of Prince Christopher of Greece and became the governess of his son, Michael.) Short of