Antiochus is the King of Antioch. He is an evil man who sleeps with his daughter and wants to keep her all to himself.
As such he devises a riddle that any man wishing to marry her must solve; when they do not, he gets to cut off their heads. He is one of the most powerful men of the region, but does not go to war when poisoning an enemy will serve just as well. His realization that Pericles has guessed his secret sets the prince off on his wanderings. He dies when he is hit with a bolt of lightning.