When Theseus arrived at the palace of Athens, he found his father, Aegeus... but also the dangerous sorceress Medea. She had married Aegeus after fleeing from Jason, had a son with the king, and wanted that son to inherit the throne — not Theseus.

"Who is this young stranger?" asked Medea, her voice sweet as honey but full of venom.

"I do not know," said Aegeus. "But he has defeated every bandit on the road. It is remarkable."

Medea looked at Theseus and understood who he really was. She saw the likeness to Aegeus, and she resolved to be rid of him before the king could recognize him.

"My king," she murmured, "this stranger may be dangerous. He may be a spy. Let me prepare a cup of wine for him, as hospitality."

But in secret, Medea mixed a deadly poison into the wine.

At the banquet, Theseus sat at the royal table, and Medea brought him the poisoned cup.

"Drink, young hero," she said with a false smile.

Theseus was about to drink when he drew his sword to cut his meat. Aegeus saw the weapon and knew it at once: it was his own, the sword he had hidden beneath the rock sixteen years before.

"Wait!" cried Aegeus, striking the cup from Theseus's hand. The poisoned wine spilled across the floor, withering the plants it touched.

"This sword is mine," said the king, trembling. "You... you are my son? Theseus?"

"Yes, Father," Theseus smiled. "I came from Troezen. I moved the rock and brought your sandals and your sword."

Aegeus embraced his son, weeping for joy. Medea, seeing her plan undone, fled the palace in her flying chariot drawn by dragons, never to return.

Athens celebrated the prince's return. But the joy did not last. Days later, a black ship arrived from Crete, and from it came the soldiers of King Minos.

"It is time for the tribute," they announced.

The people of Athens groaned in horror. Theseus did not understand, and Aegeus explained with sorrow. Years before, a prince of Crete had died in Athenian lands, and King Minos had blamed Athens, defeated the city in war, and imposed a terrible tribute: every nine years, seven young men and seven young women had to be sent to Crete, to be given to the Minotaur.

"The Minotaur?" asked Theseus.

"A monstrous creature, half man, half bull. It lives in the Labyrinth, a palace of endless corridors built by Daedalus. No one who enters ever finds the way out."

The families of Athens wept as the young people were chosen by lot. Fourteen to die. Theseus could not bear it.

"No. I will go in the place of one of them."

"No!" cried Aegeus. "I have only just found you. I cannot lose you."

"Father," said Theseus firmly, "I am the prince of Athens, and it is my duty to protect my people. And I will do more: I will kill the Minotaur and end this tribute forever."

"It is impossible," said Aegeus. "No one survives the Labyrinth."

"I will find a way," Theseus promised.

With a heavy heart, Aegeus agreed.

"Sail with the black sails, as all the tribute ships do. But if you defeat the Minotaur and survive, change the sails to white on your return. Then, from far off, I will know you are alive."

Theseus promised he would remember.

The ship sailed for Crete. The young Athenians were terrified, but Theseus kept up their courage.

"Do not lose hope. I will fight the Minotaur and bring us all home."

When they arrived, they were led to the palace of King Minos. In the watching crowd stood Ariadne, the king's daughter. She looked at Theseus, so brave and so noble, and felt she could not let him die.

That night, Ariadne slipped down in secret to Theseus's cell.

"I am Ariadne, the king's daughter," she said. "I want to help you. But I ask something in return."

"What?" asked Theseus.

"Take me with you when you escape, and marry me. I cannot bear to live any longer on this island where my father feeds people to a monster."

Theseus looked at her. She was beautiful and brave.

"I promise. But how can I defeat the Minotaur and find my way out of the Labyrinth?"

Ariadne brought two gifts. The first was a sword that glowed faintly in the dark. The second, the more important one, was a simple ball of thread.

"The Labyrinth is impossible," she explained. "A thousand corridors, all alike. But tie the end of this thread at the entrance and unwind it as you go. On the way back, simply follow the thread to the way out."

It was brilliant in its simplicity. Theseus kissed Ariadne's hand.

"You are as wise as you are beautiful."

The next morning, Theseus and the other thirteen young people were led to the entrance of the Labyrinth. The door swung open, revealing darkness and endless corridors. Theseus tied the thread of Ariadne to the doorpost and, with courage, went in.

Theseus pressed on into the Labyrinth, unwinding the thread, while the other young people stayed near the entrance, afraid to go deeper. The corridors never ended: left, right, stairs going up, stairs going down, empty chambers, dead ends. But Theseus kept going, always holding the thread.

And then he heard it. A heavy breathing. Heavy footsteps. And a roar that echoed off the stone walls, not quite human, not quite animal.

The Minotaur.

Theseus turned a corner, and there it stood. The Minotaur was immense, with the muscled body of a man and the massive head of a bull, its horns sharp as spears. Its red eyes burned with fury.

The Minotaur saw Theseus and charged. Theseus escaped the horns by a hand's breadth, and the monster crashed into the wall, making the whole Labyrinth shudder. Theseus struck with his sword and wounded the creature's shoulder, but the Minotaur was far too strong and barely felt the cut.

Striking back, the monster hurled Theseus against the wall, and he felt his ribs crack. The Minotaur charged again, and Theseus rolled across the floor, the horns passing where his head had been a second before. It was a deadly dance: Theseus was faster, the Minotaur was stronger, and a single mistake would be the end.

Then Theseus had an idea. When the Minotaur charged once more, he did not throw himself aside: he leapt upward and seized the horns. The monster roared and shook its head violently, but Theseus did not let go.

With all his strength, Theseus twisted the Minotaur's neck. The beast bellowed in pain, and Theseus twisted harder, until the monster's neck broke and it toppled over, lifeless.

Theseus stood, wounded and exhausted, but victorious. The terror of Crete was dead. He followed the thread back, hand over hand, turn after turn, until he saw the light of the entrance again. The other young people shouted for joy when they saw him alive.

"The Minotaur is dead," Theseus announced. "We are free."

Outside, Ariadne was waiting. When she saw Theseus, she ran into his arms.

"Now we run," he said.

Theseus, Ariadne, and the thirteen young Athenians ran for the harbor. Before setting sail, Theseus stove in the hulls of Crete's warships, so no one could pursue them. And they sailed away on the black ship, leaving the island behind.

On the voyage home, though, something strange happened. The ship stopped at the island of Naxos for water, and during the night Theseus had a dream. The god Dionysus appeared before him.

"Theseus, Ariadne is not for you. She is destined to be my wife. Leave her on Naxos."

Theseus woke confused and torn. Should he obey a god? But he had promised to marry Ariadne. Sorrowfully, he decided to obey. While Ariadne slept on the beach, he and the Athenians sailed away.

When Ariadne woke, she saw the ship already far off, and she wept alone on the sand, calling for Theseus. Then Dionysus came to comfort her.

"Do not weep, Ariadne. Theseus was only a mortal. I will make you my immortal wife."

And so it was. Ariadne became a goddess, the wife of Dionysus.

Theseus sailed on, sad and distracted by the loss of Ariadne. So distracted that he forgot to change the ship's sails. They remained black.

Meanwhile, in Athens, Aegeus kept watch. Every day he climbed the cliff and searched the sea for his son's ship. Until one day he saw sails on the horizon. A ship was drawing near. And the sails were black.

"No," murmured the old king. "Theseus is dead. My son is dead."

Overcome by a grief too great for his heart, Aegeus threw himself from the cliff into the sea. Ever since, that sea has been called the Aegean Sea, in memory of the king who died of sorrow.

When Theseus came ashore, glad to have saved the young people and defeated the Minotaur, the terrible news reached him: his father was dead.

"The sails," Theseus wept. "I forgot to change the sails."

He cried bitterly. His greatest triumph had become his greatest tragedy: he had saved fourteen lives, but lost his own father through a moment's forgetting.

Theseus became king of Athens and ruled wisely for many years. He united all the cities of Attica under Athens and planted the first seeds of democracy. But he never forgot his two great losses: Ariadne, whom he loved and left, and Aegeus, the father he found and lost.

The stories of Theseus went on, with many more adventures. None, though, became as famous as the day he entered the Labyrinth and defeated the Minotaur.