As the sun sets the Goddess of Love, Venus, descends upon the lofty banks of the the Tiber in search of her beloved Mars. Her son Cupid teases her for thinking that the God of War would remain faithful to her, for where Mars reigns Cupid frolics. Venus upbraids her son for his cruelty. Mars enters declaring that his love for Venus is sweeter even than warfare. She rebukes him for his seductive lies. In a duet they eventually declare their love for each other, but with trepidation and reservations. Cupid boasts that because of his great power love that does not proceed from him is doomed to failure. Mars reproves Cupid for his arrogance, but the son of Venus declares that although he is but a naked boy, his powers are superior to those of Mars. They then prepare to test their mettle in battle, but Venus calms Mars. The God of War then tries to seduce her with sweet words, but she is fearful of his deceit. Both Cupid and Mars flaunt their military valor in arias. After Cupid departs the two lovers resolve their fears and promise their faithful love for each other. As the serenata ends Cupid returns with the happy news that it is the birthday of the new King of Spain, Philip, who unites the Ebro, Seine, Tagus and Tiber. All three applaud his reign and in a final aria Cupid acclaimes his glory, wishing him long life. -Thomas Griffin