Who was Theseus's father?

The story behind the answer

Theseus’s father was Aegeus, the king of Athens. He left a sword and sandals under a heavy rock for his future son to find; when Theseus lifted the rock and claimed them, Aegeus recognized him as heir. Aegeus later gave his name to the Aegean Sea: believing Theseus had died in Crete (after he forgot to change his ship’s black sails to white), the grieving king leapt into the sea.

To remember: Aegeus → Aege