|During the Byzantine era and later during the Frankish
occupation, the coasts of the Aegean suffered from incessant
pirate raids. The islanders were forced to move their settlements
to more inaccessable areas and fortify them. They constructed
watch towers with bells as an early warning system.
In 1207, Santorini was incorporated into the Duchy of the
Archipelago, with the capital on Naxos island under the Venetian
Marco Sanudo (he ruled from 1207–1227).
Marco Sanudo gave the island the name Santorini, which is
said to have been taken from the church Santa Irini on Thirassia
island, a place suitable for anchorage at the time. Nowadays
there is strong evidence that the Basilica
of Agia Irini at the base of the mountain of Mesa Vouno
gave Santorini its name, and not the chapel of Santa Irini
The Venetians established a feudal system on Santorini and
built fortified castle settlements at Skaros, the capital
in those times, and in Oia, Pyrgos, Emporio, and Akrotiri.
The feudal lords on the island lived in Goulades, tower structures
that served as both defensible strongholds and as warehouses
for the agricultural crops.
The Venetian occupiers brought the Roman Catholic religion,
and for following centuries, Catholics and the original Orthodox
peoples of the island co-existed more or less in harmony.
Evidence of this religious freedom is found in some of the
churches built during that period that featured dual altars:
one for the orthodox, and one for catholic services.