Apollonia or Apollonia-on-the-Rhyndacus was an ancient town near the Rhyndacus river in northwesternAnatolia. Strabo placed it in Mysia, causing some to misidentify the site as Uluabat on the western shore of Lake Uluabat. However, the site is actually the promontory tombolo on the northeastern shore, near modernGölyazı. The remains of Apollonia are inconsiderable. The Rhyndacus flows into the lake and issues from it a deep and muddy river. The lake extends from east to west and is studded with several islands in the northeast part, on one of which is Gölyazı, but the dimensions vary greatly through the seasons. It is known that nine cities were built named as “Apollonia” in Anatolia within the process of ancient period. “Apollonia ad Rhyndacum” is the city built on the peninsula and islets reaching to the lake called as “Apolyont” which was named as “Artynias” or “Apolloniatis” in earlier times located on the north east of Mysia. The name of “Apollonia ad Rhyndacum” was chosen in order to differentiate from other cities in the Ancient Era with reference to the stream “Rhyndacus ” located close to the city and stemming from Aizanoi. It is thought that the islet known as Kız Ada was the Sacred Area of Apollo in Ancient Era. After the construction of the temple in the name of preservative God of the city, head of Apollo, kithara, plectron and Apollo Sauroctonus figure in the temple were used from Hellenistic Era to the late Roman Empire Period. Usage of crawfish figure continued its prevalence while depiction of Gorgon head gradually decreased. Different characters were used on the coins such as Demeter and Tyche due to the coming of new cults to the city in Roman Period.
Apollonia ad Rhyndacum is one of many ancient Greek cities that bear the name of Apollo. Inhabitants of Apollonia believed that their original colony had been founded by Miletus under the auspices of Apollo of Didyma, so Apollo was its archegetes. The antiquity of the colony and of its name is supported by coins from as early as 450 BCE, which bear the anchor symbol of Apollo and which have been attributed by some scholars to this Apollonia. The city experienced prosperity under the Attalids during Hellenistic times.