immortal horses who were given to Peleus
as a wedding gift from the gods.
When Achilles went to fight in Troy he took them with him and lent then to Patroclus. The horses mourned Patroclus bitterly when he died, and Zeus took pity on them and gave them strength to run back to the Greek camp.
Achilles then reproached them for not protecting his friend but Xanthus old him it was the will of the gods, since Hector had Apollo by his side and that Achilles soon would join Patroclus. The Furies then struck Xanthus dumb.