Ahti Sonninen (1914-1984) studied theory and composition at the Sibelius Academy in 1939–47). He taught at the Sibelius Academy in 1957–77 and was director of the East Helsinki Music Institute in 1965–84. He was made an honorary professor in 1974.
His best-known compositions are the smaller ones such as the beloved Christmas song Rauhaa, vain rauhaa Peace, Perfect Peace) but he scored success with the ballet Pessi ja Illusia (Pessi and Illusia), which was premiered in Helsinki in 1952 and broadcast on TV. Sonninen’s early works, particularly Sinfonisia tuokioita (Symphonic Moments, 1946–47) and Rhapsody, were bold experiments in modernism, but neo-classical impulses and the influence of archaic Finnish music came to dominate. He wrote also much music for young performers, e.g. Music for Young Cellists.
Fennica Gehrman publishes several of Sonninen's works, including his popular pieces for string orchestra such as Five Nordic Melodies, and his orchestral songs, e.g. Liai’s Aria from the opera Merenkuninkaan tytär (The Daughter of Neptune).