Kedrai (Kedreai, Kedreiai, Sedir Island) is on Sedir (Sedre) Island on the east coast of Keramos Bay (sinus ceramicus) (present-day Gökova). It should be noted that the biggest feature of Kedrai is its sands. These are not actually sand, but formed after the precipitated seashells underwent a chemical reaction, and there are 1-2 more places in the world. They grow in the shallow bottom of warm seas, in waters saturated with Calcium Carbonate, in turbulent belts near the coast. They are in the form of shells wrapped in layers like a hailstone, each membrane-thin shell formed by the juxtaposition of numerous needle-like calcite (aragonite) crystals.

Carbonate precipitation occurs at the bottom when carbon dioxide, which is dissolved in the calcium bicarbonate fresh groundwater and plays a role in dissolving the limestone, turns into gas during the wave turbulence and leaves the environment. Aragonite crystals, which develop in the form of needles in water, are wrapped on a grain of sand. The frictions put these materials in a polished state. This is how these tiny marbles, which are not like sand, which are the biggest feature of the cedar island, are formed. This magnificent formation, which reached the entire coast and even the ancient settlement inside ten years ago, can only be seen in the sea today. Unfortunately, that white foamy beach has turned into soil today.

The word Kedrai is thought to come from the Luwian language. It probably changed to Kedrai or Kadrai in the Hellenic language, meaning “city of the people of Kadra”. The information about the history and establishment of this city, whose people are described by Xenephon as “half Greek half Barbarian”, is limited.

Hekataios of Miletos talks about the settlement here in the VI century BC. The city joined the Caria Union in 404-428 BC, and then joined the Attica Delos Marine Union and gave an annual fee of 3000 drachmas. In 439, this fee was reduced to 2000. Xenophon besieged the Spartan commander Lysandros Kedrai in the Athens-Sparta war in 405-406 BC, and captured the city, which was next to the Athenians. He also sold his people in the slave market to punish them. After this incident, Kedrai never regained his former glory.

In the time of Xenephon, there were also some Carians, other than the old inhabitants of the city. The city came under the rule of Rhodes in the 2nd century BC, this situation caused a change in religious belief. In the II-I century BC, the cults of Apollon Pythios and Apollon Kedrieus, two important cults, were administered by the same priest. After 170 BC, an important person from Peraia of Rhodes also administered two cults at the same time. As an expression of their gratitude to the Kedrai Emperor Vespasianus under Roman rule, they also gave an honorary title.

The city walls, the Temple of Apollo, the Theatre, the Agora and the necropolis area have survived from Kedrai. Of these, the city walls surround almost the entire coast, starting from the east of the island. The rectangular prism-shaped fortification stones are in very good condition. The walls are reinforced with square bastions. Among these, a monumental bastion that reflects the most beautiful workshop of the Hellenistic period, sitting on a four-level pedestal on the south side of the island, is distinguished from the others with its careful workmanship. Not all of the walls were built at the same time.

In the east of the city, the temple of Apollo on the platform supported by the terrace walls is in the Doric style. This temple is located in the middle of a sacred ground surrounded by a perimeter wall. Some pedestals can be seen next to the thresholds and sills of the entrance doors of this sacred site. The inscriptions have been damaged so much that they cannot be read. There are traces of 3 cylindrical altars, two of them with garlands and one with a snake relief. The snake is an animal related to Apollo according to mythology. Based on this, it can be said that this temple was dedicated to Apollon Kadrieus (Apollo Pythos). In the early Byzantine period, a basilica-plan church was built over the temple. We see pieces containing the cross with the monogram of Jesus from this period.

On the eastern slope of the island, there is a theater that has survived to the present day. Limestone was used in this building as in the others. The cavea part and the seating levels are in very good condition. Its plan is in the shape of a horseshoe, considerably larger than a semicircle. The point that draws attention here is that it is quite large for a small city. From this, we can think that a large number of spectators came to the games held here from time to time. The unsymmetrical parados walls were made with a very meticulous craftsmanship. Skene, on the other hand, remained completely underground.

The Agora is likely to be on the beach; because there are pieces such as postaments and Ionic column bases, which were worked with a good stonework. There is also a BC, made with meticulous workmanship here. There is also a wall fragment that may belong to the 4th century.

The necropolis of the city is on the mainland opposite the island. Most of them are sarcophagi. In addition, pits and burial chambers can also be seen.