The temple of Apollo was built in the VIth century BC, but it was destroyed by the Persians to punish the Milletans for their rebellion. In 334 BC, Alexander the Great liberated the cities of Ionia. The construction of the new temple lasted for centuries and actually its decoration was never entirely completed. It is hypaethral temple without a roof.
Sources:
- Ekrem Akurgal, Ancient Civilisations and Ruins of Turkey: From Prehistoric Times until the end of the Roman Turkish Historical Society Press, Ankara 1970, pp. 222-231
- http://penelope.uchicago.edu/~grout/encyclopaedia_romana/greece/paganism/didyma.html
- Persius Digital Library - Didyma, Hellenistic Temple of Apollo (Building)