It is situated 22 km. south east of Cesme. The earliest findings date to the Bronze Age. Its name is believed to have come from the ancient Greek word “erythros” meaning “red” or “red town”, because the soil around the town is deep red.
Through the ages, Erythrai came under the control of various rulers and was influenced by their particular civilisations. In the 7th century B.C. as an Ionian city, Erythrai was a member of Pan-Ionian League. The city gained fame as a producer of millstones during the period of tyrannical rule. After then Lydians and Persians took control of the city. In 334 B.C. Erythrai was conquered by Alexander the Great to be followed by the kingdom of Pergamon. When this kingdom merged with the Roman Empire, Erythrai was gained the status of independent city.
At this time, Erythrai was renowned for its wines, goats, timber and millstones as well as the female oracles of Cybl and Athenias. The city was famed for being the birth place of Heracleides, the student of Herophilos who was the leader of the school of dogmatic physicians. During the earthquakes and wars, most of the city was damaged in the first century B.C.
During the Byzantium period the city lost its importance.
In 1336, Erythrai came under the rule of the Turks and the name changed as Ildır, its present name.

The remains of the acropolis and theatre were found in the excavations. The traces of a temple at the highest point of the acropolis and city walls were discovered. Other findings are pottery, bowls, stone and clay figures, vases and statues from the 6th and 7th centuries.