Although hinting at the larger scale of the Esterházy symphonies, No 20 can only date from the Morzin period owing to the presence of trumpets and drums in the score. They did not exist in the Esterháza orchestra until about 1773. Nor was this Haydn’s first ‘trumpets and drums’ C major symphony: No 37 (more likely to be the true No 2) contains them in one source, and Nos 32 and 33 (similarly closer to the early teens in true chronology) present themselves as a matching pair. This festive use of the orchestra derives from the numerous solemn Masses composed in the key during the eighteenth century and carried into purely secular (though possibly still celebratory) realms. One other characteristic of these C major symphonies is their adoption of the four-movement structure that would become the symphonic norm. Here Haydn writes a lengthy first movement in which the development section is notable for being almost as long as the exposition. The slow movement is again for strings alone, as is the trio to the Minuet. The finale is a lively movement in triple time with a central section in the minor.
from notes by Matthew Rye © 1993