We rejoin Perseus' wedding-feast, which devolves into a riot when Andromeda's uncle Phineus, whom she was promised to marry, threatens to throw a spear at Perseus for stealing his intended. Cepheus argues that Andromeda's death sentence effectively ended their engagement, and that Perseus' rescue (and Phineus' lack of a rescue attempt) makes Andromeda rightly his bride. Phineus hurls the spear at Perseus anyway, but misses, and Perseus flings the spear back, missing Phineus but killing one of Phineus' companions. A fight begins, and Athena arrives to protect Perseus, who kills Athis, a beautiful young javelin thrower, and his lover. Finally, Perseus ends the battle by turning all his enemies to stone with Medusa's head.
Minerva then travels to Thebes, where she asks the muses whether their fountain truly came to be after Pegasus stomped his hoof there. They affirm the tale and show Minerva the fountain, taking pride in their sanctuary. They tell Minerva about Pyreneus, king of Parnassus, who tried to abduct them and hold them in his palace, only to fall from his death from a tower as they escaped through the air. Minerva comments on nine birds with human-like voices, whom the muses say were nine sisters who challenged them to a singing contest with the nymphs as arbiters. The sisters were transformed to magpies when they lost.
One of the muses, Calliope, then sings Minerva the song that won her the nymphs judgment, starting with the story of the rape of Proserpine. One day, the giant buried under the isle of Sicily began to move so much that Dis, the King of the Dead, feared it would destroy his kingdom. He left the kingdom of the dead to survey the situation, at which point Venus told Mercury to strike him with love's arrow, as he was the only creature immune to love's passion. Venus designed for Pluto to fall in love with Cere's daughter Proserpine, a virgin, because Venus disdains virginity. Dis, struck by Cupid's arrow, seized her and dragged her to the Underworld, despite her struggle and the attempt of a nearby nymph, Cyane, to stop him. Despairing that her pond has been defiled, Cyane almost melted away. Meanwhile, Ceres searched everywhere for her daughter.
After long searches, Ceres met Cyane, who showed her Prosperpine's ribbon. Furious and despairing, Ceres took her anger out on the farmers of this land, ruining their harvest. Another nymph informed Ceres that Proserpine had become the queen of the underworld. Furious, Ceres asked Jove to intervene and restore her daughter. Jove considered that Ceres' lack of consent annuls the marriage and agreed to release her if she has not eaten of the food of the dead, for the Fates insist that any who have cannot leave the Underworld. Prosperine had eaten seven seeds of a pomegranate, an act witnessed by Ascalaphus, and so at first was forbidden from leaving, but Jove decreed that Proserpine spend half the year with her mother and the other half with her husband. Hence during Spring and Summer, when Proserpine is aboveground, Ceres is happy and crops flourish; during Autumn and Winter, however, Proserpine lives in the Underworld and Ceres refuses to let crops grow.
Calliope then sings of Arethusa, the nymph who told of Proserpine's capture. She relates that one day, while bathing, Alpheus spotted Arethusa and pursued her. Diana came to Arethusa's assistance, creating an impenetrable cloud around Arethusa, but Alpheus continued to pursue her until at last Diana transported Arethusa through secret caverns, during which transport she sees Proserpine in the Underworld, until she settled at Ortygia, the sacred fountain. Calliope continues to sing, turning to the story of how Ceres gave Triptolemus precious seeds and told him to use them to repair the lands she had destroyed after Dis raped her daughter. Triptolemus took the seeds to Lyncus, the king, and Lyncus jealously tried to steal the seeds and kill Triptolemus. Ceres turned the king into a lynx for his attempted slaying. The Muses tell Minerva that after Calliope was finished with her song, the nymphs judged the Muses to be victorious, and after the sisters refused to accept defeat graciously, they were changed into magpies.
The Muses' story reminds Minerva of another challenge to the gods. A mortal, Arachne, who was very good at weaving, declared that she was better even than Pallas Athena. Disguised as an old woman, Athena gets Arachne to say that she would engage Athena in a contest. She then shakes off her disguise and the contest begins. Athena represents her argument with Neptune over the right to name the city which became Athens and also weaves four scenes of hubristic mortals. Meanwhile, Arachne weaves images of Jove raping and seducing women, including Europa with Jove the bull, Asterie with Jove the Eagle, and Leda with Jove the swan. Arachne continues with images of Neptune, Apollo, and Bacchus all raping mortals. Unable to defeat Arachne and enraged at her choice of theme, Athena tears her weaving and strikes her. Arachne loops a piece of rope around her own neck to kill herself, but Athena changes her into a spider instead.
Niobe, a childhood friend of Arachne, does not learn from her fate. The wife of Amphion and Queen of Thebes, Niobe is proud of many things but proudest of all of her children. One day Manto, Tiresias's daughter, asks the women of Thebes to make sacrifices to Latona and her children, Diana and Apollo. All the women obey except proud Niobe. She walks through the streets, describing her divine lineage, and declaring that she is more fit for worship than Latona, who wandered the earth because no one would give her a piece of land on which to bear her sacred children. Niobe especially emphasizes how many more children she had than Latona, fourteen to her mere two. Latona seeks justice for this hubris, and the gods agree. Apollo kills Niobe's seven sons with arrows and Niobe is informed both of their deaths and that of her husband, Amphion, who killed himself in sorrow. Niobe taunts Latona further, saying that she is happier in her sorrow than Latona ever was in her joy. More arrows kill six of her daughters, leaving only Niobe's youngest, who is also killed in time. Niobe's body turns to stone in her grief and she is carried to the country of her birth, where tears still flow from her marble eyes.
We segue to another tale about Latona: at a site in Lycia an old alter commemorates the spot where Latona gave birth to Diana and Apollo. After giving birth at that place, Latona came to a lake, where she tried to quence a burning thirst. The men of the place wouldn't let her, and in revenge they were transformed into frogs. Another storyteller relates a flute-playing challenge to Apollo by the satyr, Marsyas, who was flayed after he lost. So many wept Marsyas fate that the river Marsya was formed from their tears.
The company mourns the loss of Amphion, their king, and his children. They blame Niobe, whose brother alone mourns for her. Kings from throughout the world come to pay their respects. Only Athens' king is absent, as he is caught up in a war with barbarians. Tereus of Thrace leads the defense of Athens, and Pandion, King of Athens, gives him his daughter, Procne, in marriage. Their wedding is a ghastly affair -- Juno, Hymen and the Graces are absent, but the Furies and the Eumenides are in attendance. Nonetheless, the pair marries and has children. Five years later, Procne asks her husband to bid her sister, Philomela, come visit them. Tereus goes to fetch her, only to be overwhelmed with lust for Philomela upon seeing her. He convinces Philomela to come aboard with him under the pretense of visitng Procne, but takes her instead to a fortress in the woods, where he imprisons and rapes her. After, she asks why he doesn't kill her because she will surely reveal his crime otherwise. Tereus cuts out her tongue to keep her from talking. He then arrives home and tells Procne that her sister is dead. She believes him.
A year later, Philomela conceives a plan to reveal her fate. She weaves the tale into a cloth and has it delivered to Procne, who is overwhelmed with rage, though she manages to hide it and plan revenge. That night is the festival of Bacchus and Procne dresses herself up as a reveler, making her way to the fortress in the woods and rescuing her sister. Procne is set on revenge, and she determines, despite her love for her son, to kill him and feed him to his father. While Tereus eats he calls out for his son, and Procne reveals her act. Tereus calls on the furies and attempts to kill the women, but before he can, Procne becomes a nightingale and Philomela a swallow. Tereus too becomes a bird. Pandion, father of Procne and Philomela, dies upon hearing the news and the kingdom passes to Erectheus, who has four sons and four daughters, two of them extremely beautiful. One of these, Cephalus, makes a happy marriage. The other, Orithyia, cannot have her beloved Boreas because of his connection to Tereus. Then, one day, Boreas realizes that as the God of the north wind he must seize his love without consent. He takes Orithyia and marries her, and they have twin boys, who grow wings like their father. When these two boys are older, they sail as Argonauts in the quest for the golden fleece.
The stories of this section of the poem continue to illustrate the key dynamic between gods and mortals -- mortals continue to challenge the gods and the gods continue to smite the mortals. As in previous sections, the gods rule by fear and strength. Indeed, we see in the story of Dis, Proserpine and Ceres that even among immortals a hierarchy of power determines events. Dis, one of the most powerful of gods, is not prevented from kidnapping Proserpine. Only afterwards, when Ceres withholds her services, does Jove intervene. Thus the gods, no less petty than mortals, take from one another, rape one another, and rob one another, only finding compromise under the threat of chaos. It's also important to note that, yet again, the most powerful god of all is Love, who is able to manipulate even Death.
Also in this section two major competitions are depicted: the nine sisters challenge the Muses to a singing competition and Arachne challenges Athena to a weaving competition. Why, one is tempted to ask, would a mortal be so foolish as to challenge a god? Even if the mortal won she or he could be certain of being punished. In depicting these irrational displays of hubris, Ovid captures human stubbornness and perserverence. The skilled, the wise and the loving among humanity don't accept the inferior status that gods demand of them, even though such resistence inevitably ends badly for the mortal. Thus Ovid's mortal challengers win the reader's sympathy to some extent -- even against the hopeless odds of their own mortality, they strive to best the gods. And in this light, the gods' lack of justice renders them quite tyrannical. Arachne, for instance, is in fact likely a better weaver than Athena. Her audacious talent, coupled with her subject, which decries the immorality of the gods' conduct with mortals, makes her in the end a martyr to the capricious immortals. She is perhaps even the hero of the tale, even though we hear it from Athena's point-of-view.
That said, Ovid certainly invites his readers to recognize that the challenging mortals are offensive to the gods because of their boasting, not because of their talent. The nine sisters go directly to the Muses and demand a competition. Arachne and Niobe challenge the goddesses by brazenly declaring their superiority to anyone who will listen. Niobe's claims are so damaging, because like Arachne's, there is truth to them. Niobe can clearly show that her claims to divinity are essentially as good as Latona's. If Latona ignores her boasts, not only will her divinity be put into question, but the very concept of divinity -- of a superior race of beings who deserve their higher status -- would be shaken. Thus the horrific punishment visited upon Niobe boldly emphasizes the true difference between god and human: mortality. Humans can be killed, gods cannot; that is the only basis on which gods "deserve" to be worshipped.
A related theme introduced in this section concerns mortal acts of revenge. When Procne discovers her husband's betrayal, she feeds him his own son. This might seem unsuitable, as it hurts Procne as much as Tereus. However, Ovid presents emotional transformations as frequently as physical transformations, and the destruction of Procne's sister damages Procne beyond repair. It upends her family, replacing hate for Tereus where she once felt love, and so she expresses the replacement of love with hate by killing her son. Transformed by grief and revenge, Procne is an utterly new creature capable of unspeakable cruelty. Thus Tereus is transformed by love and Procne by hate; both have thus abandoned both family and humanity, and they both change into birds.