Daniel Leeson’s intriguing suggestion that the opening ten-note theme of Cherubino’s Act 1 aria in Mozart’s Le nozze di Figaro is immediately taken up by Basilio in the following trio, in order to indicate that he has overheard the page sing, raises a number of very thought-provoking questions. As the clear implication of this idea is that the theme of ‘Non so più’ was composed before, or at least in conjunction with, ‘Cosa sento’, it will be interesting first to look at the original manuscripts to see if they provide any chronological support. In an honest, if perhaps slightly regret-tinged comment on the value of his work on Mozartean watermarks, Alan Tyson wrote: ‘It is the destiny of paper-evidence to be suggestive rather than conclusive.’ As it transpires, this remark sums up very effectively the sources for ‘Non so più’. Suggestive they certainly are, but, as is so often the case, a chasm remains between observable physical features such as ink colours, watermarks, paper types, corrections and revisions, and any particular theory of compositional intent that might be based on them. In this instance it would be unwise to claim that the palaeographic evidence provides direct support for Leeson’s thesis; on the other hand, it certainly poses no obstacle to it, and it raises interesting questions about the circumstances in which this very fine aria was composed.