Pelias (/ˈpiːlɪˌæs/; Greek: Πελίας) was king of Iolcus in Greek mythology, the son of Tyro and Poseidon. His wife is recorded as either Anaxibia, daughter of Bias, or Phylomache, daughter of Amphion. He was the father of Acastus, Pisidice, Alcestis, Pelopia, Hippothoe, Amphinome, Evadne, Asteropeia, and Antinoe.
Tyro was married to Cretheus, with whom she had three sons, Aeson, Pherês, and Amythaon, but she loved Enipeus, a river god. She pursued Enipeus, who refused her advances. One day, Poseidon, filled with lust for Tyro, disguised himself as Enipeus and from their union were born Pelias and Neleus, twin boys. Tyro exposed her sons on a mountain to die, but they were found by a herdsman who raised them as his own, as one story goes, or they were raised by a maid. When they reached adulthood, Pelias and Neleus found Tyro and killed her stepmother Sidero, for having mistreated her. (Sidero hid in a temple to Hera but Pelias killed her anyway, causing Hera's undying hatred of Pelias.) Pelias was power-hungry and he wished to gain dominion over all of Thessaly. To this end, he banished Neleus and Pherês, and locked Aeson in the dungeons in Iolcus (by the modern city of Volos). While in the dungeons, Aeson married and had several children, most famously, Jason. Aeson sent Jason away from Iolcus in fear that Pelias would kill him as an heir to the throne. Jason grew in the care of Chiron the centaur, on Mount Pelium, to be educated while Pelias, paranoid that he would be overthrown, was warned by an oracle to beware a man wearing one sandal.