Symphony No. 90 in C major, Hoboken I/90, was written by Joseph Haydn in 1788 as part of a three-symphony commission by Count d'Ogny for the Concert de la Loge Olympique.[1] It is occasionally referred to as The Letter R – referring to an older method of cataloguing Haydn's symphonic output. This triptych also includes Haydn's own Symphony No. 91 and Symphony No. 92.[2]