Opera did not remain confined to court audiences for long. In 1637, the idea of a "season" (Carnival) of publicly attended operas supported by ticket sales emerged in Venice.
Monteverdi had moved to the city from Mantua and composed his last operas, Il ritorno d'Ulisse in patria and L'incoronazione di Poppea, for the Venetian theatre in the 1640s.
His most important follower Francesco Cavalli helped spread opera throughout Italy. In these early Baroque operas, broad comedy was blended with tragic elements in a mix that jarred some educated sensibilities, sparking the first of opera's many reform movements, sponsored by the Arcadian Academy, which came to be associated with the poet Metastasio, whose libretti helped crystallize the genre of opera seria, which became the leading form of Italian opera until the end of the 18th century. Once the Metastasian ideal had been firmly established, comedy in Baroque-era opera was reserved for what came to be called opera buffa.