Da capo aria

A ternary form (ABA) aria. First section in tonic, second section in a related key, then, repeat of ‘A’ probably with ornamentation. A usual tonal plan for da capo arias is as follows:

A............................ B...............

Keys (major): I... I to V... V to I... // vi to iii D.C.

Keys (minor): i... i to III.. III to i... // ? to v D.C.

Note the Phrygian ending at the end of section B which provides a iii to I tonal switch byreturning to the beginning in major keys. This plan provided the basis for many Baroque concerto movements (see ritornello). Most da capo arias start with a ritornello section.