Symphony No.13 in D major, Hob. I:13

A typical symphony at this time was written for a pairs of oboes and horns and strings, but the Eisenstadt orchestra had recently taken on two new horn players, and Haydn wrote this symphony for an expanded ensemble of one flute, two oboes, four horns, timpani and strings (violins divided into firsts and seconds), violas, cellos and double basses, with bassoon doubling the bass-line. The timpani part in the autograph score is not in Haydn's hand, but it is quite possibly authentic: he may have written it on a separate sheet, with somebody else adding it to the score at a later date.