No 18 is one of the most antiquated of these works in terms of form. Haydn adopted (and adapted) the movement pattern of the church sonata, an instrumental form originally designed for liturgical use (in effect a larger-scale, orchestral version of the organ voluntary). The most characteristic aspect of this form is its opening slow movement, displacing the more characteristically symphonic opening allegro. The church sonata was usually in four movements, but here Haydn omits the traditional finale component. Instead, the symphony features, in addition to the ‘Andante moderato’ (which, incidentally, contains an opening theme in which Haydn seems to be alluding to the form’s Baroque origins in its dotted rhythms), a lively ‘Allegro molto’ and a Minuet and trio.
from notes by Matthew Rye © 1993