The city was founded from 900-1000 BC by Aeolian colonists from Lesbos, who specifically are said to have come from Methymna. The settlers built a Doric Temple to Athena on top of the crag in 530 BC. From this temple Hermias of Atarneus, a student of Plato, ruled Assos, the Troad and Lesbos for a period of time, under which the city experienced its greatest prosperity. (Strangely, Hermias was actually the slave of the ruler of Atarneus.) Under his rule, he encouraged philosophers to move to the city. As part of this, in 348 BC Aristotle came here and married King Hermeias's niece, Pythia, before leaving to Lesbos three years later in 345 BC. This 'golden period' of Assos ended several years later when the Persians arrived, and subsequently tortured Hermias to death.
The Persians were driven out by Alexander the Great in 334 BCE. Between 241 and 133 BC, the city was ruled by the Kings of Pergamon. However, in 133 BC, the Pergamons lost control of the city as it was absorbed by the Roman empire.
St. Paul also visited the city during his third missionary journey through Asia Minor, which was between 53-57 AD, on his way to Lesbos. From this period onwards, Assos shrunk to a small village, as it has remained ever since. Ruins around Assos continue to be excavated.