The next story is about Achilles' killing of Cyncnus, who had once been a beautiful woman named Caenis. Cyncnus turned into a bird upon being killed.
Nestor then tells the story of the Centauromachy, which was fought at the wedding of the Lapith king Perithous (Peirithoos) and Hippodameia after the Centaurs, unused to alcohol, became intoxicated and tried to abduct the bride -- abduction being a common theme in Metamorphoses, as well. With the help of the Athenian hero Theseus, the Lapiths won the battle. Their story is commemorated on Parthenon marble metopes housed at the British Museum.
The final story of Metamorphoses Book XII is about the death of Achilles.
Piero di Cosimo was a Florentine painter who helped with the painting of the Sistine Chapel. Be sure to click the "full-size" link since this wide painting is especially compressed. There is a female centaur in the foreground.