Evidence and archaeological findings indicate that Agios Efstratios has been inhabited since prehistoric times. Many identify it as the mythical island where, according to Homer,Philoctetes, the hero of the Trojan War, remained wounded and exiled .

During the Byzantine times, the island was a dependency of the Monastery of Great Lavra on Mount Athos. It then acquired its present name, thanks to Hosios Efstratios the Miraculous, who lived as a hermit on the island, exiled from the Byzantine iconoclasts. What follows is the period of Ottoman rule until October 18, 1912, when a Greek contingent disembarked on the island, setting it free without a fight, as the population was purely Greek.

From 1929 on, Agios Efstratios (or Ai Stratis) begun to function as a place of exile for "lefties" by decree of the Venizelos government. The phenomenon culminated during the years of Metaxas dictatorship and, while there was a break between 1941 to 1947, the camp of Ai Stratis reopened to welcome political prisoner .from spring 1947 amid the Civil War.

Among the prisoners were also several intellectuals, such as Yiannis Ritsos and Menelaos Lountemis. If you crave for more information, just visit the excellent Museum of Democracy!

The camp of Ai Stratis was closed in 1964, but unfortunately this was a decade that reserved an unpleasant surprise to the island's residents. On February 20, 1968 an earthquake razed the settlement, 20 lives were lost in the ruins, and only a few houses were left standing. The government decided to make a new settlement in an adjacent position, and most of the old houses were demolished.

This earthquake actually gave the final blow to the island, as many residents left it permanently. Today, nearly 300 residents live in Agios Efstratios and they do welcome with a smile every visitor who wants to spend a few days on their island.