Joseph Haydn gave lessons in singing, keyboard instruments, theory, and composition throughout his life. His pupils included Ignaz Pleyel, Sigismund Neukomm, and the Pole Franciszek (Franz) Lessel. In October 1805, the latter received from his teacher the autograph score of his Symphony No. 56, dating from 1774. This symphony forms a pair with Symphony No. 55, known as 'The Schoolmaster', dating from the same year. Both are included in this eighteenth volume of the Haydn2032 series, along with Symphony No. 29 (1765), "whose finale Presto sounds as if a swarm of naughty children had just escaped from a strict teacher," writes Christian Moritz-Bauer. Giovanni Antonini and the Kammerorchester Basel also recorded the finale of Lessel's Fifth Symphony in G minor, the only movement that has survived from his complete orchestral works, which include five other symphonies.

This recording is the first of a collaboration between Rene Jacobs, the Kammerorchester Basel, the Zurcher Sing-Akademie and Alpha Classics and will involve the release of four albums between 2025 and 2028; the first of these is the Missa Cellensis, then three albums devoted to Haydn's last six masses. Haydn was commissioned in 1766 to write a Missa Solemnis, the Latin term for a fully scored mass with trumpets and timpani; it is the third and largest of Haydn's fourteen masses. It was under this erroneous name that the 1766 Missa Cellensis remained known until 1975, when a fragment of the autograph score containing the title page, Kyrie I and Christe was found in Bucharest and revealed that Haydn had in fact composed two Missæ Cellenses. It is the first of these (1766) that is recorded here. Rene Jacobs puts all his expertise and enthusiasm at the service of this music that he loves so much, in collaboration with soloists with whom he works regularly, an orchestra that is also a longstanding partner, and the remarkable choir of the Sing-Akademie of Zurich.