Written by Lydia Serrant, Contributing Writer, Classical Wisdom
In ancient times, Turkey’s Didyma was not a city of trade or agriculture but a place of worship. Located on the country’s western coast, Didim — as it is now called — is home to the magnificent and ancient Apollo Temple. 
An artist’s imagining of the Apollo Temple Didyma during its construction. Credit: unknown German Artist, 1912
While it is considered a lesser-known temple today, the Apollo Temple at Didyma was incredibly significant in its time. It was important not just for the Greeks, but the Romans and the rest of the Mediterranean world as well.
Second only to the Apollo at Delphi, this temple was wider than the Parthenon in Athens and the fourth-largest temple in the ancient Greek world. Many famous (and infamous) western emperors visited the temple at Didyma. Many even vied to become its patron due to the great social, cultural, and political influence the Didymaion oracle had over Anatolia and other Greek and Mediterranean provinces.
Caesar, Julian, and even Alexander the Great passed through the city of Miletus and headed straight to Didyma to consult with the Didymain Oracle. It was here, in 303 BCE, that Emperor Diocletian traveled to consult the oracle. He heeded its advice — which was to persecute the growing Christian population.
But it wasn’t just its famous visitors that made the Apollo Temple great. The building itself stands testament to the true genius of Greek engineering and architectural design. The structure has several features that set it apart from other Hellenistic temples. Firstly, the exterior of the building is typical of large Ionic temples of its time, with a double colonnade surrounding the interior walls and a vestibule at the front, which is enclosed by a portico and projecting sidewalls. But these are the only features the Apollo at Didyma has in common with its contemporaries. 
Here is how it differed: First, the interior of the building has the most unusual design. The great stairway that leads up to the temple is large, wide enough to receive the large festival processions that traveled in from the town of Miletus via the Sacred Way. But upon ascending the steps, the worshippers were met by a huge blank wall instead of a traditional central doorway. The sacred inner sanctuary was accessed instead by two arched doorways sloping downwards on either side, leading to an open-air courtyard. These entrances were extremely narrow, only allowing for single-file access — which suggests that entrance to the inner sanctum was somewhat exclusive. 
Image of the Inner sanctuary from atop the inner staircase. Photo credit: Lydia Serrant
The open-air courtyard itself is said to have been lined with bay trees. The sacred spring (naiskos), believed to be the source of the power of the oracle, was enshrined in the center of the sanctuary, along with an impressive statue of the god Apollo. The foundations of the inner sanctuary stood in the middle of the courtyard can still be seen, along with the remains of various altars.
Processional view of the Temple on approach. The now crumbled wall would have blocked worshippers from viewing the sacred inner sanctuary. Photo credit: Lydia Serrant
The sanctuary was built to rival the Temple of Artemis in Ephesus, which was the largest temple until Apollo. The temple access was built to deliberately prevent a direct approach. Visitors of lesser importance were thus prevented from seeing the inner ‘secrets’ of the temple. Instead, a second inner courtyard lay atop of the wall, which was accessed by 22 steps over 15 meters wide that lead up from the inner courtyard below. It is believed that the purpose of this unusual layout was to allow some worshippers a tantalizing glimpse of the inner sanctum, the priests, and the prestigious visitors that graced its halls.
Unfortunately, there are no surviving accounts of the ritual or ceremony involved in consulting the oracle from the perspective of the enquirer. Instead, we are left with historical and procedural inference from other sources to explain the unusual design layout of the temple. 
Indeed, the history of the Temple of Apollo at Didyma itself contains mysteries. The site was razed and rebuilt many times. In fact, a humble structure of worship stood there even before the Ionic colonization of the Aegean coast. A second much larger structure was built by the people of Miletus and was destroyed in 494 BCE by the Persians. The site was left in ruin until Alexander the Great conquered the region and reconstructed it in 331 BCE. The temple flourished once more under Roman control, with Emperor Caligula allegedly trying to complete the project. In 101 AD, the Sacred Way was restored by Emperor Trajan. The Apollo reconstruction continued until the closing of pagan temples under Theodosius I. Didyma later became a bishop’s seat under the rule of Justinian I. The site was eventually abandoned and left to ruin after the Ottoman conquest of Iona in 1300, and an earthquake in 1493 finally destroyed the temple almost completely.
The ‘end’ point of The Sacred Way a 16.5km processional road that connected the Sacred gate of Miletus to the steps of the Apollon Temple at Didyma. Photo credit: Lydia Serrant
Yet the Apollo stands to this day, its size is still hugely impressive, with 25-meter high walls. The temple platform area covers some 5,500 square meters and contains 122 columns over two meters in diameter and some 28 meters in height. Such feats of engineering have puzzled archaeologists for over 200 years. Temple construction could take hundreds of years to complete, so ancient Greek architects and engineers would engrave project plans within the stones of the temple itself, and polish them away once the project was complete. Since the last reconstruction was never completed, the site is awash with inscriptions, diagrams and floor plans from the original builders. Many tourists visit this site daily, unaware that ancient knowledge lies preserved underfoot and for all to see.
Etchings made by ancient builders visible at the base of the External temple Columns. Photo credit: Lydia Serrant
In 1979, a team of archaeologists visited the site and were astonished at the preservation of these plans. They report finding finely etched lines on the Temple walls that trace out the intended design of various structures, some of which were never completed. These ancient ‘blue prints’ cover a huge area, and have shed light on the building methods and  mathematical precision employed at the time.
Examples of etchings, initials, insignias, and quotations found along the exterior steps running along all four walls of the temple. Including various etchings, shapes and designs found on the temple floor. Photo credit: Lydia Serrant
Inscribed on the floors of the outer sanctuary are plans for the construction and decorating of the columns. Using micro-imaging techniques, horizontal lines were discovered on the unfinished walls of the inner sanctuary that show plans for building column shafts and their plinths. 
Doodles, names, and dates of the construction workers can also be found littered across the site — there are even a few quotations from the oracle.
A possible etching of the sun god Apollo. Apollo was often depicted with a shield and spear. A bird or raven appears on his left side. Raven was commonly associated with the god. Photo credit: Lydia Serrant
The Temple of Apollo at Didyma is a magnificent structure and testament to the ingenuity of those who designed, built, and inscribed it. The site played an important role in the history of the Greek conquest of Anatolia and the politico-cultural reach of the Anatolian Greeks and their later Roman counterparts. 
The site is still cherished by those who live and visit the modern town of Didim. In some ways, the site remains faithful to its original purpose: bringing people together. The Temple of Apollo at Didyma is still a favored location for cultural festivals, community workshops, and a place for local artists, farmers, traders, and visitors to commune. Adjacent to the ruined temple is a modern mosque, demonstrating that despite the modernization of the immediate area, the modern Apollo Temple site remains part of an unbroken tradition of worship and community that stretches back over 2,000 years.
Haselberger, L. (1985). The Construction Plans for the Temple of Apollo at Didyma. Scientific American, 253(6), 126-133. Retrieved June 21, 2021, from https://www.jstor.org/stable/24967878
Parke, H. (1986). The Temple of Apollo at Didyma: The Building and Its Function. The Journal of Hellenic Studies, 106, 121-131. doi:10.2307/629647