In Greek mythology, Theseus is one of a group of heroes which also includes Perseus, Achilles, Jason, Odysseus, Hercules, and Bellerophon. Theseus' story begins with his father, Aegeus. Aegeus was the king of Athens and he received a prophecy at Delphi that he didn’t understand. He told his friend King Pittheus the prophecy, and Pittheus realized that Aegeus was destined to have a great son, so Pittheus presented his daughter, Aethra, to Aegeus and got Aegeus drunk.
Before he returned home to Athens, Aegeus placed his sandals and sword beneath a very large rock, and told Aethra that if she conceived a son and if the son could lift the rock, she should send their son with the tokens to Athens, where he would be acknowledged. When he returned home, however, the sorceress Medea had come and taken refuge in the city and charmed Aegeus, so that in the end, he married her, and they had a son, Medus.
Aethra did bear a son, and Pittheus gave out that his father was Poseidon. He was given the name Theseus. When Theseus was sixteen, Aethra took him to the rock, which Theseus easily lifted, recovering the sandals and sword. Aethra told him his true history, and he set out for Athens. On the way, he rid the land of several murderous criminals, as well as a monster sow who had killed several people and ruined their crops. His last adventure prior to reaching the city was in the home of Procrustes who stretched or cut his guests to make them fit on his bed. Theseus killed Procrustes as well.
When Theseus arrived in court, Medea recognized him, but told Aegeus that the visitor was a stranger who was seeking the throne. Medea got Aegeus to send Theseus to fight the Cretan bull, hoping he would die in battle, but he won. So Medea planned to poison him in a dinner at the palace, but Aegeus recognized the sword he had left under the rock, and knocked over the poison goblet, forcing Medea and her son to flee Athens.
Aegeus then explained the plight facing the Athenians. The son of King Minos of Crete had been murdered in Athens years before. In recompense, the Athenians were obliged to send seven young men and seven maidens each year to feed the Minotaur in the Labyrinth on Crete. Theseus determined to place himself among the sacrifice victims and see what he could do, despite his father’s horror. So he sailed for Crete, promising to fly white sails on his return if all is well.
In Crete, he immediately had words with Minos, and much to the king’s surprise, recovered — with the help of Poseidon’s consort — a ring that Minos had thrown into the harbor to test Theseus. Ariadne, Minos’ daughter, saw the whole thing, and fell in love with Theseus. She secretly explained the Labyrinth to Theseus, gave him a ball of thread to guide himself through the Labyrinth and concealed a sword inside for him to use in killing the Minotaur.
Theseus killed the Minotaur, released the other Athenian youths, and raced home, with Ariadne. It is not clear why, but she is left behind in Naxos on the trip back to Athens. But Theseus forgot his promise to fly white sails, and his father threw himself into the sea, giving it its name, the Aegean.
Theseus’ adventures as king of Athens include marrying an Amazon, hunting the Calydonian boar, abducting Helen of Troy, and an attempt to steal Persephone from Hades. It was Theseus who gave sanctuary to Oedipus in his final hours and cared for Hercules when he went mad. Theseus married Ariadne’s sister Phaedra, but Aphrodite’s interference created a tragedy, and he was afterwards deposed and banished. His life ended when he became the guest of the king of Scyros, and the king, not wanting the trouble of having Theseus around, pushed him to his death and told everyone that the old man had lost his balance and fallen accidentally.