Unlike Miletus or Priene, Didyma was not a city, but a place of worship dedicated to the god Apollo. The temple of Apollo, as an important oracle shrine, was only surpassed in its size by the Artemision in Ephesus and the Heraion in Ionia. Today it is one of the best preserved large buildings of antiquity.

With its length of 120 m and an original height of 25 m, Didymaion was one of the largest temple buildings of antiquity. The preserved ruin gives an impressive idea of this enormous architectural achievement. Despite centuries of construction, the temple was never completed.

Of the planned 122 columns, 72 were upright, but not all had already been finished. The front side was finished up to the final timberwork. The high quality of the building ornaments can be seen in the pieces preserved.

The columns stood on richly profiled bases decorated with reliefs in the front row. The crowning glory are ionic capitals of the people. The capitals of the corner columns are unique. One still shows remains of the figures of Artemis and Leto, the other (in the archaeological museum in Istanbul) shows Zeus and Apollo, each between lion grips and bull heads.

On the three-part architrave lay a frieze with Medusan heads. Representations of this monster averted disaster from the temple according to ancient belief. On top there was a frieze of mighty, cuboid teeth with plant ornaments on the front sides. Capitals with winged female figures growing out of a plant ornament adorned the upper ends of the protruding temple walls.

Herodotus, the father of historiography, reports that the Ionians immigrated around the turn of the 1st millennium B.C. and took over an older place of worship, where in pre-Greek times a female natural deity was venerated. However, this has not yet been verified archaeologically.

According to legend, Leto gave birth to her son Apollo at the oracle site of Zeus. The legend goes on to say that Apollo later appeared to a local shepherd named Branchos and gave him the gift of vision. The Carian priesthood of the Branchids, who until the Persian Wars were the namesakes and rulers of the Shrine, traced back to these shepherds. The priests of the Shrine were later also appointed in Miletus and belonged to prestigious families of the city.

The oracle probably had an international reputation as early as the 7th century BC. This is proven on the one hand by Herodotus, who reports on consecration gifts from the Egyptian Pharaoh Necho and the Lyder King Kroisos, and on the other hand by the actual discovery of numerous consecration gifts.

Herodotus reports that the Persian king Darius plundered the temple and burnt it down after the fall of Miletus in 494 BC. Other sources report a destruction in 479 BC by the Persian king Xerxes. Archaeological evidence of fire destruction cannot be found for either 494 or 479 BC. The fact is, however, that no new construction measures have taken place over the next 150 years. In the last third of the 4th century BC, the previously regional sanctuary became part of the city of Miletus. Milet gave the order to build the new temple of Apollo and appointed yearly officials and sacrificial priests.

The religious operation of the oracle came to a standstill in the course of the 4th century with the onset of Christianity. In late antiquity Didyma was bishop's seat and was honoured by Emperor Justinian I. with the title Iustinianopolis, before the place experienced a rapid decline in the early Middle Ages. From the 10th to the 12th century Didyma was once again the seat of a bishop. Twice, in the 7th and 15th centuries, earthquakes destroyed Didyma. The latter led to the abandonment of the settlement. It was not until the end of the 18th century that the town was resettled. The place has been explored since the 18th century. First by English, then French, finally by German archaeologists. According to this, found objects from Didyma can be found in the British Museum in London, the Louvre in Paris and the Pergamonmuseum in Berlin.

Inside the temple. Free stairs to a cult hall, on the left one of the tunnel passages to the outside

The holy road to Miletus

From the 6th century B.C., an 18 km long "holy" road, a processional route, connected ancient Miletus with the temple.