The Oracle of Delphi

Delphi was considered the centre of the world. Zeus released two eagles from opposite ends of the earth and they met there, and a carved stone called the omphalos — the navel — marked the spot. The site belonged to the earth goddess first; Apollo took it by killing the serpent Python that guarded it, and the priestess who spoke for him was called the Pythia in its memory.

The procedure was elaborate. Petitioners paid, sacrificed, and waited — sometimes months, since the oracle originally operated one day a year and later only monthly. The Pythia sat on a tripod over a chasm, and what she said was interpreted and set into verse by attendant priests before it reached the questioner.

The famous answers are famous because they were traps. Croesus of Lydia was told that if he attacked Persia he would destroy a great empire; he attacked, and the empire he destroyed was his own. The oracle told Athens to trust in wooden walls before the Persian invasion, which Themistocles argued meant ships, and he was right — but only because he won.

That is the Delphic pattern. The prophecy is never wrong and never quite says what you took it to say, and acting on it is usually what makes it come true. Oedipus, Perseus's grandfather and Laius of Thebes all took precautions against Delphic prophecies, and the precautions were the mechanism.

Two maxims were carved at the entrance: know thyself, and nothing in excess. For a site people travelled hundreds of miles to consult about the future, the advice at the door was about themselves.