Certain sources give Agenor as a son of Jasus, and, in some mythological traditions, father of the giant Argus Panoptes. In other accounts, Agenor was said to have been the son and successor of Triopas, and accordingly brother of Jasus, Xanthus and Pelasgus. Hellanicus of Lesbos states that Agenor was instead a son of Phoroneus, and (again) brother of Jasus and Pelasgus, and that after their father's death, the two elder brothers divided his dominions between themselves in such a manner that Pelasgus received the country about the river Erasmus, and built Larissa, and Jasus the country about Elis. After the death of these two, Agenor, the youngest, invaded their dominions, and thus became king of Argos.