Theseus persuades his father to allow him to go to Crete, with the aim of killing the Minotaur. And if he kills the creature he will signal his success by flying a white sail on the return journey.

He’s similarly nonplussed at Sounion, a few miles outside Athens, and site of Aegeus’s suicide when his son Theseus returned from slaying the minotaur but forgot to hoist the white sails that ...