Didyma was an ancient Ionian sanctuary, the modern Didim, Turkey, containing a temple and oracle of Apollo, the Didymaion. In Greek didyma means "twin", but the Greeks who sought a "twin" at Didyma ignored the Carian origin of the name. Next to Delphi, Didyma was the most renowned oracle of the Hellenic World, first mentioned among the Greeks in the Homeric Hymn to Apollo, but an establishment preceding literacy and even the Hellenic colonization of Ionia. Mythic genealogies of the origins of the Branchidae line of priests, designed to capture the origins of Didyma as a Hellenic tradition, date to the Hellenistic period.
Didyma was the largest and most significant sanctuary on the territory of the great classical city Miletus. To approach it, visitors would follow the Sacred Way to Didyma, about 17 km long. Along the way, were ritual waystations, and statues of members of the Branchidae family, male and female, as well as animal figures. Some of these statues, dating to the 6th century BC are now in the British Museum, taken by Charles Newton in the 19th century.