What kind of stories provided the basis for earliest operas?

The earliest operas were based on stories from Greek and Roman mythology, as well as stories from the Bible. These stories were often about love, betrayal, and revenge, and they provided a rich source of material for opera composers. Some of the most popular stories used in early operas include:

* Orfeo ed Euridice (1607), by Claudio Monteverdi, tells the story of Orpheus, who travels to the underworld to rescue his wife Eurydice.

* La Dafne (1597), by Jacopo Peri, tells the story of Daphne, who is transformed into a laurel tree to escape the advances of the god Apollo.

* L'Arianna (1608), by Claudio Monteverdi, tells the story of Ariadne, who is abandoned by her lover Theseus on the island of Naxos.

* Il ritorno d'Ulisse in patria (1641), by Claudio Monteverdi, tells the story of Odysseus's return to his home island of Ithaca after the Trojan War.

These early operas laid the foundation for the development of opera as an art form, and they continue to be performed today.