Solo song with instrumental accompaniment in opera , cantata , or oratorio .
The strophic or stanzaic aria, in which each new stanza might represent a melodic variation on the first, appeared in opera in Claudio Monteverdi 's Orfeo (1607) and was widely used for decades. The standard aria form с 1650–1775 was the da capo aria, in which the opening melody and text are repeated after an intervening melody-text section (often in a different key, tempo, and metre); the return of the first section was often virtuosically embellished by the singer. Comic operas never limited themselves to da capo form. Even in serious opera, from с 1750 a variety of forms were used; Gioacchino Rossini and others often expanded the aria into a complete musical scene in which two or more conflicting emotions were expressed. Richard Wagner 's operas largely abandoned the aria in favour of a continuous musical texture, but arias have never ceased to be written.