Colchis lay on the eastern shore of the Euxine Sea, the Black Sea, at the mouth of the river Phasis, in a land of extraordinary fertility and strangeness. The Greeks knew it as a place where the rivers ran with gold, where the mountains touched the sky, and where the rules of the Mediterranean world did not apply. Its king was Aeetes, the son of Helios, the sun god, and of Perseis, an Oceanid nymph. Aeetes had come to Colchis from Corinth, where he had ruled before being driven out by his brother Perses, and he had brought with him the secrets of fire and sorcery that his father the sun had taught him. He established his capital at Aea, a city of gleaming walls and sacred groves, and he ruled over a people who were famous throughout the ancient world for their skill in magic and metallurgy.

The greatest treasure of Colchis was the Golden Fleece. The story of how it came to the kingdom began in Boeotia, where Athamas, the king of Orchomenus, had married Nephele, a cloud nymph created by Zeus, the king of the gods who ruled from Mount Olympus with his thunderbolt. Athamas later abandoned Nephele for Ino, the daughter of Cadmus, and Ino plotted to destroy Nephele's children, Phrixus and Helle. She convinced the women of the kingdom to roast the seed corn so that no crops would grow, then bribed the messengers sent to Delphi to return with a false oracle: Phrixus must be sacrificed to save the land. As the boy was led to the altar, Nephele sent a flying golden ram with a fleece of pure gold to rescue her children. Phrixus climbed onto the ram's back, and Helle followed him, but as they flew over the strait that separates Europe from Asia, Helle lost her grip and fell into the water below. The strait was named the Hellespont, the Sea of Helle, in her memory. Phrixus survived and rode the ram all the way to Colchis, where Aeetes received him with hospitality. In gratitude, Phrixus sacrificed the golden ram to Zeus and gave its miraculous fleece to Aeetes, who hung it in a grove sacred to Ares, the god of war, where it was guarded by a dragon that never slept.

The dragon was no ordinary beast. It was enormous, with scales that gleamed like bronze and eyes that glowed with a baleful light. It never closed its eyes, not even for a moment, and its coils encircled the oak tree on which the fleece hung. No thief had ever succeeded in passing it. The grove itself was sacred ground, protected by the god of war, and anyone who entered without permission risked not only the dragon's fangs but the wrath of Ares himself. The fleece gleamed in the darkness of the grove like a captured sun, its gold so pure that it lit the surrounding trees with a pale radiance. For years it hung there, a prize that every adventurer dreamed of and none dared to claim.

That changed when Jason arrived. The young prince of Iolcus had been sent by his uncle Pelias to fetch the fleece as an impossible task designed to kill him. Jason sailed the Argo, the first ship ever built, with a crew of fifty heroes that included Heracles, Orpheus, and the Dioscuri. When they reached Colchis, Aeetes received them with suspicion and rage. He recognised the foreign ship as a threat to his kingdom and his treasure, but he could not openly murder guests without offending Zeus, the god of hospitality. Instead, he set Jason a series of impossible tasks. First, the young prince must yoke two fire-breathing bulls, enormous beasts with hooves of bronze and breath that could melt stone. Then he must plough a field with them and sow four acres with dragon's teeth. Finally, he must defeat the crop of armed men, the Spartoi, who would spring from the earth and attack him. Aeetes had performed these tasks himself, and he knew that no mortal could survive them.

But the gods had already decided Jason's fate. Hera, the queen of Olympus and goddess of marriage, hated Pelias and wished to see him overthrown. Athena, the grey-eyed goddess of wisdom and war, had designed the Argo itself and favoured Jason above all mortals. And Aphrodite, the goddess of love and beauty, sent her son Eros, the winged god of desire, to shoot Medea, the daughter of Aeetes, with an arrow that made her fall desperately in love with the foreign hero. Medea was a priestess of Hecate, the goddess of witchcraft, and she possessed knowledge of herbs and incantations that her father had taught her. She approached Jason in secret, gave him a magic balsam that made his body fireproof, and instructed him to throw a stone into the midst of the armed men, who would then attack each other rather than him. Jason yoked the bulls, ploughed the field, sowed the teeth, and when the Spartoi sprang from the earth, he threw a boulder into their midst. Confused by the blow, the warriors turned on one another and slaughtered themselves.

Aeetes was not bound by his word. He planned to burn the Argo and kill the crew. Medea, foreseeing this, led Jason to the grove of Ares in the dead of night. She drugged the sleepless dragon with a potion of herbs and incantations, and Jason snatched the Golden Fleece from the tree where it hung. The fleece gleamed like a thundercloud, and its weight was that of a young ram. They fled to the ship, and Medea joined them, bringing her young brother Apsyrtus with her. When Aeetes gave chase in his own ship, Medea committed the most terrible act of her life. She murdered Apsyrtus, cut his body into pieces, and threw them overboard. Aeetes, compelled by paternal grief, stopped to gather the fragments of his son, and the Argo escaped into the open sea.

Colchis remained in Greek imagination as the land of gold and magic. Herodotus, the father of history, described the Colchians as Egyptians by descent, claiming that they were the descendants of Sesostris's army. The Greeks believed that the rivers of Colchis carried gold dust down from the Caucasus Mountains, and that the Colchians collected it by placing fleeces in the stream, allowing the heavy gold particles to lodge in the wool. This practice, which may be the historical origin of the Golden Fleece myth, continued into the modern era. In the 1st century CE, Strabo described the gold-washing techniques of the Colchians, and Pliny the Elder wrote of the gold mines of the region. Today, the land of Colchis is part of western Georgia, and the river Phasis is the modern Rioni. The myth of the Golden Fleece has become the national symbol of Georgia, a reminder that the greatest treasures are sometimes guarded by the most terrible monsters.