Youskevitch, Igor, 1912-94, Russian-American ballet dancer. He joined (1938) the Ballet Russe de Monte Carlo and became premier danseur. Youskevitch danced with the Ballet Theatre in New York from 1946 to 1955, thereafter returning to the Ballet Russe de Monte Carlo as artistic director and dancer, and then retiring to teach in the 1960s. He was famous as a master of the classic style, e.g., in Afternoon of a Faun.

Stravinsky, Igor Fedorovich, 1882-1971, Russian-American composer. Considered by many the greatest and most versatile composer of the 20th cent., Stravinsky helped to revolutionize modern music.

Stravinsky's father, an actor and singer in St. Petersburg, had him educated for the law. Music was only an avocation for Stravinsky until his meeting in 1902 with Rimsky-Korsakov, with whom he studied formally from 1907 to 1908. Stravinsky's First Symphony in E Flat Major (1907) is pervaded by the influence of Rimsky-Korsakov's nationalistic style. The work of Stravinsky interested the ballet impressario Sergei Diaghilev, and Stravinsky's first strikingly original compositions—L'Oiseau de Feu (The Firebird, 1910) and Petrouchka (1911)—were written for Diaghilev's Ballets Russes in Paris.

In the ballet Le Sacre du printemps (The Rite of Spring, 1913) he departed radically from musical tradition by using irregular, primitive rhythms and harsh dissonances. The audience at the premiere of the ballet reacted with riotous disfavor. However, in the following year the work was performed by a symphony orchestra, and ever since it has been recognized as a landmark and masterpiece of modern music.

At the beginning of World War I, Stravinsky moved to Switzerland, where he composed several works based on Russian themes, including the ballet Les Noces (The Wedding, 1923). Influenced by 18th-century music, he embarked on an austere, neoclassical style in such works as the poetic dance-drama Histoire du Soldat (The Soldier's Tale, 1918), the opera-oratorio Oedipus Rex (1927; text by Jean Cocteau after Sophocles), and the choral composition Symphonie de psaumes (Symphony of Psalms, 1930).

In the 1930s, Stravinsky toured throughout Europe and the United States as a pianist and conductor of his own works. He became a French citizen in 1934, but five years later he moved to the United States, becoming an American citizen in 1945. Compositions of the 1940s include such diverse works as the Ebony Concerto (1946) for clarinet and swing band; the Third Symphony (1946) in three movements; the ballet Orpheus (1948); and a mass (1948) for voices and double wind quintet.

After composing the opera The Rake's Progress (1951; inspired by Hogarth's engravings, with libretto by W. H. Auden and Chester Kallman), Stravinsky turned to experiments with serial techniques (see serial music). In Cantata (1952) the new technique was evident, and in the chamber piece Septet (1953) he made the full transition to serialism. He continued to compose in this exacting style in the abstract ballet Agon (1957) and in Threni (1958), a work for voices and orchestra. His creative originality was undiminished in his late works, which display remarkable freshness, meticulous craftsmanship, and an experimental quality.

Stravinsky's influence on 20th-century music is immeasurable. He revitalized the rhythms of European music and achieved entirely new sonorities and blends of orchestral colors. A series of lectures he delivered at Harvard were published as Poétique musicale (1942, tr. Poetics of Music, 1948).

Sikorsky, Igor Ivanovich, 1889-1972, American aeronautical engineer, b. Kiev, Russia. He immigrated to the United States in 1919 and was naturalized in 1928. Sikorsky built and flew the first multimotored plane (1913) and established the world's endurance record for sustained flight in a helicopter of his own design (1941). He organized corporations to manufacture airplanes (in 1923, 1925, and 1928) and became engineering manager of the Vought-Sikorsky Aircraft Division of the United Aircraft Manufacturing Corp. He is best known for his work on the development of the helicopter. In 1968 he was awarded the National Medal of Science.

Moiseyev, Igor Alexsandrovich, 1906-2007, Russian dancer and choreographer. He studied at the Bolshoi Ballet School and was later a soloist with the Bolshoi Theatre (1924-39) and ballet master there (1930-39). In 1937 he organized the Moiseyev Dance Company, a ballet-trained folk dance group. The company later toured Europe (debuting in Paris in 1955), the United States (debuting in New York City in 1958), and China and became one of the world's most popular dance troupes. With the hundreds of works he choreographed, Moiseyev created a new form of dance that distilled the folk styles of Russia and other nations into lively, virtuosic, and innovative theatrical performances. Among his best-known dances are Partisans, Pictures from the Past, and Dance of Fools; he also choreographed ballets, e.g., Salammbô (1932) and Khachaturian's Spartacus (1958) for the Bolshoi Ballet.

Igor or Ihor, d. 945, duke of Kiev (912-45), successor of Oleg as ruler of Kievan Rus. According to the Russian Primary Chronicle, a medieval history, Igor was the son of Rurik, founder of the Russian princely line. Igor's expedition (941) against Constantinople was routed by the Greeks, and in 945 he concluded a new commercial treaty with the Byzantines. He was killed by rebellious Slavic tribespeople while attempting to collect tribute. His wife, St. Olga or Olha, served as regent for their son Sviatoslav after Igor's death.

Igor (Igor Sviatoslavich), 1151-1202, Russian prince. In 1185 he was defeated by the Cumans in an expedition that was immortalized in the epic Slovo o polku Igoreve (tr. by Vladimir Nabokov, The Song of Igor's Campaign, 1960). The author is unknown, but the date of composition has been established as c.1187. The manuscript was discovered in 1795 in a 16th-century transcript containing many errors in copying. Although its authenticity has been questioned, it is considered the first notable work of Russian literature. It is remarkable for thematic unity and for imagery, particularly descriptions of nature and invocations of pagan magic. The work was used by Borodin for his opera Prince Igor.