Sons of Poseidon

And passing through Abderia he came to Liguria, where Ialebion and Dercynus, sons of Poseidon, attempted to rob him of the kine, but he killed them and went on his way through Tyrrhenia. But at Rhegium a bull broke away and hastily plunging into the sea swam across to Sicily, and having passed through the neighboring country since called Italy after it, for the Tyrrhenians called the bull italus, came to the plain of Eryx, who reigned over the Elymi. Now Eryx was a son of Poseidon, and he mingled the bull with his own herds. So Hercules entrusted the kine to Hephaestus and hurried away in search of the bull. He found it in the herds of Eryx, and when the king refused to surrender it unless Hercules should beat him in a wrestling bout, Hercules beat him thrice, killed him in the wrestling, and taking the bull drove it with the rest of the herd to the Ionian Sea.


- Apollodorus, Library, Book 2, Chapter 5, Section 10