The Florentine Camerata began meeting in the home of Count Giovanni de’Bardi in 1573. Not unlike the Council of Trent, these poets, musicians, and philosophers thought that polyphony had gone too far, and they hoped to return music to what they thought of as the pure style of the ancient Greeks. They believed (incorrectly, as we now know) that Greek drama was sung throughout, and they sought to revive it in original musical works based on Greek mythology.
This is an excerpt from one of the earliest operas, L’Eurydice (1600) by Camerata member Jacopo Peri.
Claudio Monteverdi treated the same subject in Orfeo (1607), the earliest opera for which we have the complete score.
Opera of the Baroque era used set design and stage machinery that was extremely innovative, and which some people believe has not been duplicated even in our own day. The Drottningholm Court Theatre in Sweden has preserved much of its original stage machinery, and you can see some examples here:
In addition, there were standard gestures that singers used to convey the emotional content:
When the first public theaters were built, opera became SPECTACLE:
A spectacle that drew upon costumes, sets, movement, makeup, and stage effects — in addition to virtuosic musical performances — to create an overwhelming audiovisual and emotional experience, something we’re still familiar with in live performance.