Didyma was an ancient Greek sanctuary on the coast of Ionia, 100km form Ephesus. It contained a temple and oracle of Apollo, the Didymaion. Next to Delphi, Didyma was the most renowned oracle of the Hellenic world, first mentioned among the Greeks in the Homeric Hymn to Apollo. Its establishment preceded literacy and even the Hellenic colonization of Ionia. After his capture of Miletus in 334 BC, Alexander the Great reconsecrated the oracle but placed its administration of the oracle in the hands of the city, where the priest in charge was annually elected. Until its destruction by the Persians in 494 BC, Didyma's sanctuary was administered by the family of the Branchidae. Mythic genealogies of the origins of the Branchidae line of priests, date to the Hellenistic period.