Drama musicale in a prologue and three acts by Francesco Cavalli to a libretto by Giacinto Andrea Cicognini loosely based on Apollonius's Argonautica; Venice, Teatro S Cassiano, 5 January 1648 [=1649].The only collaboration between Cicognini and Cavalli, Giasone became the most frequently performed opera of the entire 17th century. In addition to possible performances in Milan in 1649 and 1650 and Lucca in 1650, published librettos document 21 revivals in various Italian cities between 1650 and 1690 (sometimes with a different title). An unusually large number of these performances are documented by scores. It was also one of the few operas to inspire a play that led an independent existence.
A beach with a view of the island of Colchis In a celestial debate over the outcome of the impending drama, Apollo champions Medea and Cupid supports Hypsipyle as Jason's future wife.
A delicious garden with a palace, adjoining the kingdom of Colchis Hercules and Besso fear that Jason's amorous nightly activities with an unknown princess may make him incapable of stealing the Golden Fleece, an event planned for this very day. Jason shares their concern but nevertheless hopes for a successful outcome.
Rosmina, a gardener, sings a flirtatious love song (‘Per sanar quest'appettio’).
The throne room of Colchis Medea, who is the unknown princess, expresses her love for Jason. When her former suitor Aegeus arrives, she rejects him, leaving him to bewail his unhappiness.
[The nearby countryside] Orestes, sent by Hypsipyle to search for Jason, meets the stuttering hunchback Demo, from whom he vainly attempts to extract information; the two then retire for liquid refreshment. (Demo's halting delivery of his identifying song ‘Son gobbo, son Demo’, which culminates in a hilarious duet with Orestes, is one of the opera's high spots.)
[Medea's apartments] In a two‐strophe aria, Delfa discourses on the problems of fleeting youth and the frustrations of old age (‘Voli il tempo, se sè’). She sees Jason approaching and rushes off to warn Medea. Jason, who does not recognize Medea, since he has never seen her face, asks her help in capturing the Golden Fleece. She scolds him for having violated her hospitality by seducing (and fathering twins on) a noblewoman of Colchis (in fact herself), and makes him promise to marry her. He agrees because he is anxious to know his beloved's identity. She teasingly attempts to pass off Delfa as the lady in question but finally identifies herself, to Jason's great joy. The two depart, leaving Delfa to philosophize in a recitative and strophic aria (‘Troppo soavi i gusti’) on the mores of a society in which girls first prove their capacity as mothers and then get married.
Landscape with tents at the mout of the Danube, with a view of the Black Sea Hypsipyle dreams of her betrothed, Jason, father of her twin sons. On awakening, she remembers that she has left her homeland, Lemnos, with Orestes and Alinda to search for him, and wonders when Orestes will return with news.