Ios is inhabited since prehistoric times. It is one of the southest Cyclades islands, located in a strategic spot on the marine road to Crete and south Asia. It had a determinant role to the evolution of Cycladic civilization.
The archaeological findings in Skarko's hill reveal the existence of a protocycladic settlement in Ios.
Life in the island went on through all historic periods and followed the rest of Cyclades in evolution and evils.
At the end of the 2nd millenium BC Ions spread to the west coast of Minor Asia and conquered Aegean islands. Ios was then inhabited by Ion colonists from whom-according to a theory- took its name.
During classic times Ios, in order to protect itself from Persians, made an ally with Athens.
After Heronia's battle in 338BC, Ios submits to Macedonians. In 315BC takes back its freedom and becomes an equal member of the "Islands Kino". At this time the island flourishes. It has trade transactions with the other Cyclades islands and Rhodes and cuts its own coin.
During Roman times the island is turned into a banishment land.
In 1207 Enetics take over Ios as all Cyclades islands and falls under Naxos' ducat established by Marcus Sanoudos.
Naxos' dukes govern the island until 1371 when Fragiskos Krispos murders Duke Nikolao. Krispos' dynasty had total control of the island until 1517.
In 1566 Ios is taken over by Turkish who rename the island to Aine.
During the 1831 revolution, Ios had active part to all fights.
In 1829 Ios passes into the young Greek State with the convention of London.