This essay looks at the intersections between genres. In the second
half of the eighteenth century, the aria with da capo and sonata form, which the modern critical tradition tends to differentiate according to their diverse use and diverging fate (the decline of the aria with da capo starts as the sonata form is gradually establishing itself) displayed a similar compositive logic. On the basis of works by Sarti, Sacchini, Mozart and others, and by comparing the literature of several of the main essayists of the period, the overlapping of the two formal arrangements is clear to see - it is today that any distinction is actually made; at the same time reflections are made on the procedural nature of the aria with da capo and the support offered by the sonata form in the creation of a
diverse, more complex dramaturgical perspective.