In 1985, Albi Rosenthal reported his discovery of a printed libretto for the opera Andromeda, composed by Monteverdi for performance in Mantua in Carnival 1620. This libretto deserves a new examination for its dramatic content, its likely musical setting (now lost) and some fundamental questions of genre. Its patron, Prince Vincenzo Gonzaga, used the librettist Hercole Marliani to broker his self-fashioning by imitating both Monteverdi's Orfeo (1607), supported by Vincenzo's elder brother, and Arianna (1608), which in effect belonged to the prince's parents. Monteverdi was typically slow to produce the score. The customary explanation is his disenchantment with Mantua and his new duties at St Mark's, Venice. However, we now see that both the Gonzagas and Monteverdi used Andromeda, like others of his Mantuan-commissioned works, as a bargaining chip in a complex exchange of obligations and favours typical of the courtly world to which the composer still belonged.