The Symphony No. 91 in E♭ major, Hoboken I/91, was written by Joseph Haydn. It was completed in 1788 as part of a three-symphony commission from Count d'Ogny for the Concert de la Loge Olympique, [1] a successor to Haydn's series of " Paris symphonies". It is occasionally referred to as The Letter T referring to an older method of cataloguing Haydn's symphonic output.[ citation needed]This triptych also includes Haydn's own Symphony No. 90 and Symphony No. 92. [2]
The autograph manuscript bears a dedication to d'Ogny, but Haydn also gave Prince Krafft Ernst von Oettingen-Wallerstein a copy as if it were an original. [3]
The work is in standard four movement form and scored for flute, two oboes, two bassoons, two horns, continuo ( harpsichord) and strings. It is the last symphony that Haydn composed that is not scored for trumpets and timpani.
The first movement opens with a slow introduction which Haydn works into the opening allegro assai. The Allegro's first theme is derived from an idea Haydn used in his cantata Arianna a Naxos, Hob. XXVIa/2, composed the same year. The theme is chromatic, legato and in two-part inverted counterpoint. [4] The second theme is dancelike. Both the themes are closely linked with the opening largo.
The slow movement consists of a set of three variations on a theme. Listen to the bassoon and the accompanying string filigree in the first variation and the series of trills near the end of the movement.
The minuet includes a trio for the bassoon accompanied by plucked strings.
The finale opens quietly and builds gradually to a close.