Amid his official duties at Venice, Monteverdi maintained an interest in theatrical music and produced several stage works, including the substantial "Il combattimento di Tancredi e Clorinda" (The battle of Tancred and Clorinda) for the 1624–25 carnival. When the first public opera house in the world opened in Venice in 1637, Monteverdi, by then in his 70th year, returned to writing full-scale opera. He may have been influenced by the solicitations of Giacomo Badoaro, an aristocratic poet and intellectual who sent the elderly composer the libretto for "Il ritorno d'Ulisse in patria" (The return of Ulysses). For the 1639–40 carnival season, Monteverdi revived "L'Arianna" at the Teatro San Moisè and later produced his setting of "Il ritorno" at the Teatro San Cassiano. For the following season he wrote "Le nozze d'Enea in Lavinia" (The marriage of Aeneas to Lavinia), now lost, which was performed at the third of Venice's new opera theatres, Teatro Santi Giovanni e Paulo.