Although Nicolò Minato took the framework of his libretto from the seventh book of Herodotus's
Histories, as translated into Italian by
Matteo Maria Boiardo in the 15th century, the plot is actually based on a 1651 comedy by Raffaele Tauro, ''L'ingelosite speranze'', which in turn was an Italian adaptation of
Lope de Vega's 1625 Spanish comedy
Lo cierto por lo dudoso. The premiere at Venice was probably conducted by Cavalli from the keyboard. The opera was highly popular in Italy: at least nine different revivals were given there while Cavalli lived. In 1660 Cavalli was persuaded to travel to France to produce a new opera for the wedding of
Louis XIV in Paris. He soon became entangled in court intrigue which ensured that the projected opera,
Ercole amante, was not ready in time and had to be replaced by a revival of
Xerse at the last minute.
Xerse was given with ballets by Cavalli's rival
Jean-Baptiste Lully, who had become the official court composer in France. The whole spectacle lasted eight or nine hours and the French audience had little appreciation for an opera in a foreign language, preferring Lully's dance music. Surviving manuscripts including Cavalli's own annotations from performances of Xerse in Venice, Genoa, Naples and Bologna clearly demonstrate that he often amended, cut, and reorganized material as each production was being prepared. The first act begins with the well-known
aria "Ombra mai fu" ("There was never a shadow"). According to Martha Novak Clinkscale, Handel's later,
more famous setting "is neither more poignant nor mellifluous than Cavalli's". == Roles ==