Task: Question Generation
Input (English): Passage: Sergei Prokofiev graduated from the Saint Petersburg Conservatory in 1914, having by then acquired an early reputation as an avant-garde composer. His biographer Israel Nestyev asserts that the Second Piano Concerto of 1913 was "Prokofiev's ticket of admission to the highest circles of Russian modernism".When the First World War broke out in August 1914, Prokofiev avoided military service, possibly because he was the only son of a widow. During the war years he continued to compose; in May 1918, in the period of upheaval following the October Revolution and the beginning of the Civil War, Prokofiev obtained permission from the Bolshevik government to travel abroad, and left for America. His biographers have maintained that he did not "flee the country"; rather that he embarked on a concert tour, which he extended when he became convinced that his career prospects would be better served in America and western Europe. He remained in America until March 1922; he then stayed briefly in the small German town of Ettal before moving to Paris in October 1923.Rather than treating Prokofiev as a fugitive or exile, the Moscow government chose to consider him as a general ambassador for Soviet culture, and the composer returned the compliment by registering in France as a citizen of the Soviet Union, the new state formed on 20 December 1922 by Russia and the states of the former Russian Empire. Prokofiev expressed support for the political developments in what he still considered his homeland, and was keen to resume contacts there. He was accorded VIP status when he paid his first visit to the Soviet Union in 1927, for a recital tour. Further trips followed, and in 1930 Prokofiev took a flat in Moscow, although Paris remained his principal home. During this period of rapprochement he consciously sought to simplify his musical language into a form that he believed would be consistent with the official Soviet concept of art.
Output (English): What country remained Prokofiev principle home in 1930?