Archons, I come to you with a matter of great urgency. One of my most trusted Ephors has betrayed us and fled to the Persians. He must be found before he reaches their capital and sells our plans to Xerxes. He is cunning, and he will be among their ranks in some disguise - he has a forgettable face, but my guards say he left behind a sandal of unusual girth and size. You find the shoe that fits, and we have found our traitor.