The Greek theater of Assos was built in a natural rock bulge in the slope below the temple of Athens. It faces the sea and the island of Lesbos. Recent research indicates that it was built on the site of an even older theatre. Several earthquakes and landslides have hit the theatre hard. Thus, only the lower of the three tiers is completely preserved. The foundations of the ground floor of the stage house are well preserved. It was 19.5 metres wide and had two storeys. Stage house and proskenion indicate early Hellenistic origins. The construction of the stage corresponds to that of the (much better preserved) theatre of Priene.

The settlement site, a 234 m high rock of dark trachyte directly by the sea, was already inhabited in the Bronze Age. In the 7th century BC Assos was founded from Methymna on the neighbouring island of Lesbos. The city was a member of the Attic-Dellic Sea Alliance, but apparently played no role in the Greek-Persian conflicts of the 5th and 4th centuries BC. It was not until the Satrap uprising that it became significant, and in 366 BC the rebel Satrap Ariobarzanes fortified himself here.
Since about 360 BC it was under the rule of Eubulos and his successor Hermeias. At this time Aristotle also lived in Assos.
334-241 B.C. the city was located in the territory of Alexander the Great and the following Seleucids. 241-133 B.C. Assos belonged to the Empire of the Attalids of Pergamum before it became part of the Roman Empire. Still in 1306 the Greeks were able to defend the fortress of Assos, which was only in the area of the old Acropolis, against the Ottomans, but shortly afterwards the settlement became their property.