Metamorphoses Book 5: Perseus' Fight in the Palace of Cepheus
While Perseus told his new bride's family stories about his adventures, Andromeda's uncle and betrothed, Phineus stormed in with an army to reclaim the bride he'd lost to Perseus. Cepheus warned his brother to just let it go because he'd lost his claim to Andromeda when he'd not even tried to save her from the sea monster. Cepheus explained that Phineus' betrothal to Andromeda ended when Perseus saved her. Phineus refused to give up his claims, and so a bloody and gruesome battle took place in the halls of Cepheus' palace. Hundreds were killed, and Perseus fought like a champion while Phineus hid behind an altar and occasionally took shots at Perseus with a javelin. Athene appeared to her brother during the battle to give him courage. When it seemed that Perseus was nearly overwhelmed by all the men clamoring for his death, he pulled out Medusa's head and yelled at his allies to turn away. Phineus' men turned to marble statues while Phineus kept his eyes averted and tried to make a deal with Perseus. The only deal Perseus was willing to make with Phineus was to turn him to a statue like his friends that decorated the palace.
After the battle, Perseus took Andromeda with him to Argos, his ancestral city. Once there, Perseus challenged Proteus to settle and old grievance and avenge his grandfather. Perseus turned Proteus to stone as he also did to Polydectes who had sent him to retrieve the Gorgon's head so that he could seduce Danae, Perseus' mother.