Apollodorus 1.9.16
Pelias sends Jason off in quest of the golden fleece
[1.9.16] Aeson, son of Cretheus, had a son Jason by Polymede, daughter of Autolycus. Now Jason dwelt in Iolcus, of which Pelias was king after Cretheus. But when Pelias consulted the oracle concerning the kingdom, the god warned him to beware of the man with a single sandal. At first the king understood not the oracle, but afterwards he apprehended it. For when he was offering a sacrifice at the sea to Poseidon, he sent for Jason, among many others, to participate in it. Now Jason loved husbandry and therefore abode in the country, but he hastened to the sacrifice, and in crossing the river Anaurus he lost a sandal in the stream and landed with only one. When Pelias saw him, he bethought him of the oracle, and going up to Jason asked him what, supposing he had the power, he would do if he had received an oracle that he should be murdered by one of the citizens. Jason answered, whether at haphazard or instigated by the angry Hera in order that Medea should prove a curse to Pelias, who did not honor Hera, "I would command him," said he," to bring the Golden Fleece." No sooner did Pelias hear that than he bade him go in quest of the fleece.
