The Calbys river (now known as the Dalyan river) was the border between Caria and Lycia. Initially Kaunos was a separate state; then it became a part of Caria and later still of Lycia.

Kaunos was an important sea port, the history of which is supposed to date back to the 10th century BC. Because of the formation of İztuzu Beach and the silting of the former Bay of Dalyan (from approx. 200 BC onwards), Kaunos is now located about 8 km from the coast.

The city had two ports, the southern port at the southeast of Küçük Kale and the inner port at its northwest (the present Sülüklü Göl, Lake of the Leeches). The southern port was used from the foundation of the city till roughly the end of the Hellenistic era, after which it became inaccessible due to its drying out. The inner or trade port could be closed by chains. The latter was used till the late days of Kaunos, but due to the silting of the delta and the ports, Kaunos had by then long lost its important function as a trade port.

After the capture of Caria by Turkish tribes, and the serious malaria epidemic of the 15th century AD, Kaunos was completely abandoned.

The archeological research is not limited to Kaunos itself, but is also carried out in locations nearby e.g. near the Sultaniye Spa where there used to be a sanctuary devoted to the goddess Leto.

Mythology
According to mythology Kaunos was founded by King Kaunos, son of the Carian King Miletus and Kyane, and grandson of Apollo. Kaunos had a twin sister by the name of Byblis who developed a deep, unsisterly love for him. When she wrote her brother a love letter, telling him about her feelings, he decided to flee with some of his followers to settle elsewhere. His twin sister became mad with sorrow, started looking for him and tried to commit suicide. Mythology says that the Calbys river emerged from her tears.

History
The oldest find at the Kaunos archeological site is the neck of a Protogeometric amphora dating back to the 9th century BC, or even earlier. A statue found at the western gate of the city walls, pieces of imported Attic ceramics and the S-SE oriented city walls show habitation in the 6th century BC. However, none of the architectural finds at Kaunos itself dates back to earlier than the 4th century BC.

Main archeological sites
Kaunos is a site that is interesting for both its archeological and ecological importance. Situated in the Köyceğiz-Dalyan Special Environmental Protection Area, it offers outstanding vistas and is rich in wildlife. The ruins of the city are near Dalyan, on the west bank of the ancient Kalbis river. The main sights at the archeological site itself are:

The Acropolis (Persikon), situated on a 152 m high rock, fortified with Byzantine walls. The city’s acropolis was called Imbros and it lay at the foot of Mount Tarbelos (present-day “Mount Ölemez”).

Adjacent to the acropolis is a smaller fortification, called Heraklion. Until the 5th century BC this 50 m high cape reached into sea and there were two ports south and north of it. From the Acropolis there are views of the ancient city, Dalyan, the Dalyan river, the estuary and İztuzu Beach. The small fortification looks down on a traditional dalyan (fishing weir) situated quite near the former southern port.

The theater has a diameter of 75 m and was built at a 27-degree angle. It had a capacity for 5000 spectators and is in a fairly good state. It is still occasionally used for performances.

The palaestra with its Roman baths, a wind measuring platform and a domed Byzantine basilica Archaeological research has shown that the palaestra was built over part of the old city that most probably had been a place of worship.

The Roman baths served as a social meeting place and were meant to impress the Kaunians — by their sheer dimensions — of the power of the Roman Empire. In the Byzantine era the baths were dismantled and the frigidarium was re-used as a church.

The wind-measuring platform dates back to 150 BC and was used for city planning. According to the archeologists Öğün and Işık, it must have consisted of a circular building with a base diameter of 15.80 m and a top diameter of 13.70 m. The building has collapsed, however, probably as a result of an earthquake. The measuring method is therefore not quite clear. In his De architectura the Roman architect Vitruvius stated that wind-measuring platforms were used to plan streets in accordance with the prevailing wind direction, in order to keep the air in cities clean.

The domed Byzantine basilica on the palaestra terrace dates back to the 5th century AD. It was made with building materials taken from previous buildings on a foundation belonging to a 4th-century building that was probably also used as a place of worship. The archeologist team think that its inner walls were plastered and decorated with frescoes. The domed basilica is the only remaining Byzantine edifice in Kaunos that still stands. Next to the basilica mosaics have been uncovered.

The port agora is located at the flat area in front of Sülüklü Lake. It dates back to the 4th century BC and kept its function as an economic, political and social meeting place until the end of the Roman era. The remains of pedestals indicate that there must have been many (bronze) statues of influential Romans, but these have not been found. Most likely these were melted down in the Byzantine era, for the archeologists found a smelting furnace of that period near to the pedestal of a bronze equestrial statue of the Roman governor of Asia, Lucius Licinius Murena.

The covered stoa at the north side of the agora offered sun and rain protection. The stoa was created in the early Hellenistic era (3rd century BC), but part dates to the early Roman era. The Nympheon is also Hellenistic, but the fountain basin was extended during the Roman era.

The temples
Six temples have been excavated, two of Hellenistic and four of Roman origin. Probably the terrace temple of the 3rd century BC facing a circle of columns has the greatest appeal. Inside the circle an obelisk has been found, which is also depicted on old Kaunian coins. The obelisk was the symbol of king Kaunos, who according to mythology established the ancient city bearing his name.