The First Comparative Religion, and Its Method

Herodotus does something no earlier Greek writer had done systematically: he sets the religion of other peoples beside his own and treats them as versions of one another. Egyptian deities are named with Greek names throughout, Amun appears as Zeus and Osiris as Dionysus, and he argues that the Greeks took the names of most of their gods from Egypt. That habit, later called interpretatio graeca, decided how the ancient Mediterranean would think about foreign gods for centuries, and it is a method with a cost, since it makes every unfamiliar deity a familiar one in disguise.

The method he uses on evidence is worth as much. He reports what he was told, names who told him, and frequently offers two or three incompatible explanations without choosing between them; when he does not believe something he says so and reports it anyway. He tells how Croesus tested the oracles by asking each what he was doing on an appointed day, and how only Delphi answered correctly, which is a story about verification told inside a religious frame. Running under all of it is a theology of a kind: greatness attracts divine resentment, the god does not permit anyone but himself to think high thoughts, and the warning that no life should be called fortunate before it is over.