John Dryden defines opera (1685)
This discussion of opera is from John Dryden’s Preface to the opera Albion and Albanius (1685). The music of Abion and Albanius is by Grabut and Dryden is the librettist.
An Opera is a Poetical Tale, or Fiction, represented by Vocal and Instrumental Musick, adorned with Scenes, Machines, and Dancing. The Persons represented in Operas are generally Gods, Godesses and Heroes descended from them, who are supposed to be their peculiar Care; which hinders not, but that meaner persons may sometimes gracefully be introduced, especially if they have relation to those first Times, which Poets call the Golden Age; wherein by reason of the Innocence, those happy mortals were supposed to have had a more familiar intercourse with Superior Beings; and therefore Shepherds might reasonably be admitted, as of all Callings, the most innocent, the most happy, and who by reason of the spare Time they had, in their most idle Employment , had most leisure to make Verses, and to be in Love; without somewhat of which Passion, no Opera can possibly subsist.
Dryden, John, Preface to the opera Albion and Albanius, 1685 (extract).