Phineus, the former fiancé of Andromeda, bursts into Perseus and Andromeda’s wedding banquet to contest the marriage. Phineus hurls his spear at Perseus but misses. Perseus retaliates, and a melee ensues. At one point, over a thousand men surround Perseus. He turns them to stone by pulling out Medusa’s head. Phineus pleads for his life, and Perseus promises that he will not touch him with his sword. He technically keeps his word but petrifies him with Medusa’s head.
Minerva visits the virgin Muses and the spring, which Pegasus created with his hoof. The Muses begin to tell Minerva about Pyrenus, a wild Thracian man, who invited them into his house. While they are talking, the sound of nine magpies fills the air. The Muses explain that these birds were once human sisters, the nine daughters of Pierus. They challenged the Muses to a contest of song, and the Muses reluctantly accepted. The Pierides sang first, telling a story that cast the Olympian gods in a negative light. Calliope alone sang on the Muses’ behalf.
Calliope sang of Venus and Cupid, who made Dis fall in love with Proserpina. As Proserpina picks violets in a grove, Dis rapes her and then takes her to his underworld kingdom. Cyane, a nymph of Sicily, sees the crime, but all she can do is weep. Her tears make her part of the spring she inhabited. Ceres, Prosperpina’s mother, searches everywhere for her daughter. When she comes to Cyane’s spring, Cyane manages to convey what happened. The rich soil of Sicily feels Ceres’ wrath. Arethusa, a sacred spring, explains to Ceres that Dis, not the earth, is to blame. After grieving, Ceres speaks to Jupiter. Initially, Jupiter says that Dis raped Proserpina out of love, and that Proserpina married well. The brother of Jupiter is no insignificant son-in-law. Jupiter says that if Ceres still wants Proserpina back, she may have her, as long as Proserpina has not eaten anything from the underworld. Proserpina has eaten something, so Jupiter offers a compromise. Proserpina will divide her time equally between Dis and Ceres.
Arethusa tells Ceres she was transformed from a nymph into a sacred spring to escape Alpheus, a river god. Ceres takes flight in her serpent-driven chariot and gives Triptolemus seeds that cause great fruitfulness. Triptolemus travels to the kingdom of Scythia bearing this gift. The king of the land, Lyncus, is jealous and seeks to kill Triptolemus and steal his seeds. Ceres intervenes and turns Lyncus into a lynx.
At this point, Calliope ended her song, and the nymphs declared her victorious. But even in defeat, the Pierides showed such contempt that the Muses turned them into magpies.
In narrating the battle that breaks out at the wedding banquet, Ovid draws attention to the dissimilarities between himself and his literary predecessors, Homer and Virgil. Whereas those writers make much of men clashing in competition for a woman, Ovid pointedly refuses to do so. Instead of mimicking the grandeur and pomp of, for example, Odysseus’s battle with suitors for Penelope, or Aeneas’s battle with Turnus for Amata, Ovid turns his battle scene into a near farce.