Iolcos was an ancient city in Greece, in the region of Magnesia. In Greek mythology, the king of Iolcos was Aeson, but he was violently dethroned by his brother, Pelias. Pelias then forced Aeson's son, Jason, to retrieve the Golden Fleece from the region of Colchis, as a prophecy foretold of Pelias' death by Jason. Jason organised the Argonautic Expedition, and along with his fellow shipmates, collectively called the Argonauts, set sail for the mythical Colchis. After a number of adventures, they arrived in Colchis and Jason took the Golden Fleece from King Aeetes. Medea, Aeetes' daughter, fell in love with Jason and followed him back to Greece, where she became queen of Iolcos after marrying Jason.
Iolcus Is also called Iolcos.