George Balanchine, born Giorgi Balanchivadze (Georgian: გიორგი ბალანჩივაძე, Russian: Георгий Мелитонович Баланчивадзе) (January 22 [O.S. January 9] 1904 – April 30, 1983), was one of the 20th century's most famous choreographers, a developer of ballet in the United States and the co-founder and balletmaster of New York City Ballet. He was a choreographer known for his musicality; he expressed music with dance and worked extensively with Igor Stravinsky. Thirty-nine of his more than 400 ballets were choreographed to music by Stravinsky.