As is the case with so many heroes, the life of Theseus begins with at least the possibility of a miraculous conception. Theseus’s mother was Aethra, a princess in Troezen. When King Aegeus of Athens visited Troezen, the young woman’s father made his visitor drunk and gave him Aethra as a bedmate. After spending time with the drunken Aegeus, Aethra waded out to a little island where Poseidon, too, had intercourse with her. Aethra then returned to bed with Aegeus. Poseidon decided that any child born to Aethra in the next few months should be considered to be Aegeus’s even if it was his. When Aegeus awoke and found himself with Aethra, he instructed her not to tell the child who its father was, but if it was a boy, to send him to Athens only after he succeeded in lifting a rock under which Aegeus had left a sword and a pair of sandals. In time a fine boy, Theseus, was born to Aethra and after several years the boy succeeded in removing his legal father’s tokens from under the rock. Beginning his search for a father—a common motif in the heroic monomyth—Theseus left for Athens and on the way performed many feats reminiscent of the labors of Herakles. At Epidaurus he killed a famous brigand. Near Corinth he killed a notorious robber. Farther along his route he killed a monster sow and another brigand. At Eleusis he met the terrifying Cercyon, who forced any visitors to wrestle with him to the death. Theseus took up the challenge and defeated the bully. Procrustes, another bully outside of Athens, forced visitors to lie on a bed; if they were too long for the bed he would mutilate them in such a way as to make them fit it. Theseus killed Procrustes and finally reached Athens and the court of Aegeus. There he had to contend with Aegeus’s wife, the enchantress Medea, who desperately wanted Medus, her son by Aegeus, to succeed to the throne. As Aegeus had not yet recognized their visitor as his son, but only as a now famous hero who might desire his throne, he allowed Medea to prepare a poison cup for their guest. The poison plot would have worked had Theseus not used his father’s sword retrieved from under the rock to cut his meat. Aegeus recognized his sword, knocked the poisoned drink out of his son’s hand and embraced Theseus as his heir. Medea and her son were banished.

We have already seen how Theseus volunteered to go to Crete as a tribute hostage and how he killed the Minotaur there before escaping with Minos’s daughters, Ariadne and Phaedra. In a poem by the fifth-century B.C.E. poet Bacchylides, the story is told of how Minos challenged Theseus to prove that he was, as he had claimed, the son of Poseidon. Minos threw a ring into Poseidon’s sea and said only a son of Poseidon could possibly find it. Theseus dove into the sea and returned with gifts from Poseidon’s undersea court.

After the killing of the Minotaur, Theseus and his companions made their way to the island of Naxos. There Theseus deserted Ariadne, who had helped him defeat the Minotaur, but Dionysos took pity on the maiden and married her himself.