Aegeus was the founder of the city of Athens in Greek mythology, and king of the city. After failing to produce a male heir to the throne with his first two wives, he went to the Oracle of Delphi, where he was given a particularly cryptic prophecy. Seeking someone to explain it, he reached Troezen, where King Pittheus, understanding what the prophecy meant, forced his daughter Aethra upon him. After their union, Aethra also bedded Poseidon and became pregnant to Theseus. Aegeus, deciding to return to Athens, buried his armour and weapons, and told Aethra that once his son grew up, he should bring them back to him in Athens. In Athens, Aegeus married Medea, who had fled from Jason, and had a son together, named Medus.
Later, the prince of Crete, Androgeus, visiting Athens, was killed in a contest with Aegeus, enraging King Minos who declared war on Athens. However, a peace treaty was signed under the term that seven men and seven women from Athens would be sent to Crete in regular intervals to be fed to the Minotaur.
When Theseus grew up, he went to Athens where he was acknowledged by his father; soon, though, he volunteered to be sent to Crete as one of the tributes, in order to slay the Minotaur, which he successfully did. However, on the way back, he forgot to change his ship’s black sails to white, as he had told his father he would do if he succeeded; as a result, Aegeus, seeing the black sails and thinking his son was slain by the Minotaur, jumped into the sea and drowned. Since then, the sea became known as the Aegean.