By the ancient world’s tradition, it was on July 21, 356 — the night of Alexander the Great‘s birth* — that a theretofore forgettable man set fire to the wooden rafters of the Temple of Artemis in Ephesus. Situated on the Hellenized coast of Asia Minor, near present-day Selcuk, Turkey, Ephesus was one of the great cities of the Mediterranean. It counted Artemis (Diana) its patron deity, and gloried in a jaw-dropping marble temple, bankrolled two centuries before by the Lydian king Croesus, that would have nearly covered a modern football pitch. Ephesians took their Artemis seriously: 400-plus years later,...