Cretheus
Κρηθεύς
Jason's grandfather, whose contested throne launched the quest for the Golden Fleece.
He is the king who founded Iolcus.
His wife Tyro loved the river god Enipeus — and according to the underworld scene in the Odyssey, Poseidon approached her in the shape of that river's stream, and she bore Pelias and Neleus.
Cretheus's own son was Aeson. When Cretheus died, the half-brother Pelias seized the throne, and that quarrel drove his nephew Jason to the quest for the Golden Fleece.
SourcesHomer, Odyssey