Ilos, in Greek mythology, the founder of Ilion (Troy). Ilos (or Zacynthus, a Cretan name) has been identified either as the brother of Erichthonius or as the son of Tros and grandson of Erichthonius. According to legend, the king of Phrygia gave Ilos 50 young men, 50 girls, and a spotted cow as a wrestling prize, with the advice that he found a city wherever the cow first lay down. The animal chose the hill of Ate, where Ilos marked out the boundaries of Ilion. After praying for a sign from Zeus, Ilos was sent the Palladium, a statue of Pallas Athena, for which he built a temple. As long as the Palladium was kept in the temple, Troy was invincible. (It was eventually stolen by Odysseus and Diomedes.) Ilos’s son Laomedon succeeded him as ruler of the city. His daughter, Themiste, was Aeneas’s grandmother. His grandson Priam was the last king of Ilion.