Georgy Ivanovich Gurdjieff was an influential early 20th century Russian mystic, philosopher, spiritual teacher, and composer of Armenian and Greek descent. Gurdjieff's music divides into three distinct periods. The "first period" is the early music, including music from the ballet Struggle of the Magicians and music for early movements dating to the years around 1918. The "second period" music, for which Gurdjieff arguably became best known, written in collaboration with Russian composer Thomas de Hartmann, is described as the Gurdjieff-de Hartmann music. Solo piano versions of these works have been recorded by Cecil Lytle and Keith Jarrett. The "last musical period, Gurdjieff in collaboration with de Hartmann composed some 200 pieces.