The oldest residents of island were Pelasgoi, who reached Chios coming from Thessaly, Kares and Leleges. Later, Avantes and finally Ions inhabited the island. Those peoples lived in Chios for thousands of years. The people of Chios originated from those peoples who were subjugated and assimilated by the Greeks.

Stravon informs us about the people of Pelasgoi. Eustathios and Menekratis the Elaitis give us more or less the same information. With regard to the origin of Pelasgoi and their relations with other populations have been formulated various theories Ancient writers put forward many and different theories regarding the origin of Pelasgoi and their relations with other peoples, which, however, are contradictory .In any case the only thing we can be sure about is that the Pelasgoi preceded the Greeks and they were rather Indo-Europeans.

Herodotus is the first writer to inform us about the presence of Avantis on the island mentioning that they reached Chios setting off from Euboea. According to Aristotelis, their name originated from the city Ava, in Fokida, from which settlers coming from Thrace went to Euboea.
Stravonas reported that Kares also occupied the region from Miletus to the coastline of Ephesus. He also mentioned besides the Kares, the Leleges also lived in the islands of Chios and Samos and later they were expelled by Ions.
According to the Greek myth, the name of Leleges was the first name used for the tribe of Kares and that tribe lived in the islands of Aegean being subjects to the King of Crete, Minoas.
Unfortunately, the information available is rather vague and that’s why neither the origin of the peoples’ nor the time of their settlement and stay on the island can be determined,