The Argonautic expedition

The purpose of the Argonautic expedition was to fetch the golden fleece from Colchis (Aea), which lied at the end of the Black sea. The golden fleece belonged to the ram, which Phrixus used to flee from his father, the king of Orchomenos in Boeotia, and his stepmother, when they were preparing to sacrifice him. Phrixus reached the palace of king Aetes, who received him with honors and gave him his daughter. When Phrixus sacrificed the lamp to Zeus, he gave the fleece to Aetes and he hung it up in an oak, in the grove of Ares and put a sleepless dragon to guard it, day and night. 
The reason for the expedition was, as follows: king Pelias of Lokris in Thessaly, had been warned with oracles, that he would be killed by a descendant of Aeolus and to be aware of a man with one sandal. When Jason appeared with one sandal in his right leg, in order to get rid of him, he sent him to fetch the golden fleece.
In the expedition took part all the heroes of Greece, including Herakles, fifty in number. Among them were the Dioskuri, Kastor and Polydeukes, Idas and Lynkeus, Orpheus, Peleus, Meleager, Tydeus, Amphiaraos and Atalanta the huntress, the only female.
The leader of the expedition was Jason and when Herakles, who had just completed the labor of the Erymanthian boar was asked to take the leadership, he declined.
The vessel for the voyage was build by Argus, the son of Phrixus and named after him, Argo. It was build from aged pines of the mount Pelion, under the protection of Athena. It had fifty oars and in the prow, had a piece from the speaking oak of Dodona, inserted by Athena.
They set sail from Pagasae, the port of Iolkos. When the ship arrived at Mysia, Hylas the companion of Herakles, disappeared while he was looking for water and Herakles stayed behind to search for him and he did not take part anymore in the expedition. The Argonauts, after many adventures, arrived at the mouth of the river Phasis, in Colchis.
There, king Aetes promised to give them the golden fleece, if Jason would sow the remaining teeth of the dragon, which have not been used by Kadmos at Thebes and plough the two fire breathing oxen, with the brazen feet.
Jason with the help of Medea, the daughter of Aetes who had fallen in love with him, managed to acquire the golden fleece. With Medea together, they sailed for home, but in a big storm were driven to Italy. Finally after many adventures returned to Iolkos.