Lyapunov was born in Yaroslavl in 1859. After the death of his father, Mikhail Lyapunov, when he was about eight, Sergei, his mother, and his two brothers (one of them was Aleksandr Lyapunov, later a notable mathematician) went to live in the larger town of Nizhny Novgorod. There he attended the grammar school along with classes of the newly formed local branch of the Russian Musical Society, where he was taught by Karl Klindworth (an earlier student of Liszt) and Tchaikovsky's earlier student Sergei Taneyev. After receiving his diploma in 1883, he met Mily Balakirev, one of the members of the Mighty Five and decided to move to St. Petersburg. Balakirev, born himself in Nizhny Novgorod, guided the young pianist and composer, and he did so radically as he did with the other composers of the Mighty Five. Lyapunov was also involved with the collection of folk music for the Imperial Geographical Society. He succeeded Rimsky-Korsakov as assistent-director in music at the Imperial Chapel and later became teacher at the conservatory of St Petersburg (in 1911). After the Russian Revolution he chose voluntary exile and moved to Paris, where he taught Russian immigrants in music. He died of a heart attack in 1924. Lyapunov chronologically takes the spot between the Mighty Five and Tchaikovski on the one hand, and the radical composers of the later period, such as Scriabin, Stravinsky, Prokofiev and Shostakovich, on the other. This interim period produced composers of whom some, like Alexander Glazunov, joined the older generation following a friendly, soft trend, while others, such as Rachmaninoff, demonstrated the heavy, late-romantic style. Even though Lyapunov chose the late-romanticist Balakirev as his mentor, he did not really belong to either of these groups, but rather switched back and forth between them.