Original: In 1959 Messiaen was nominated as an Officier of the Légion d'honneur,Hill & Simeone (2005), p. 245 and in 1966 he was officially appointed professor of composition at the Paris Conservatoire (although he had in effect been teaching composition for years).
Simplified: In 1966 Messiaen became professor of composition at the Paris Conservatoire.