The city was founded and settled around the 9th or 8th century century bc, by Dorians from Laconia, under a Spartan leader, Theras. The site was strategically placed to dominate the maritime routes both between Crete and the Aegean, and between the Greek and Asia Minor mainlands. Below the mountain were harbours both to the north and south sides, one or other of which afforded protection whatever the direction of the wind. The principal harbour was the settlement of ancient Oea (modern Kamari) to the north, found ed probably at the same time as the city on the mountain above. The settlement of Eleusis to the south, at the harbour of modern Vlychada, seems to be a Hellenistic foundation,however: the geographer and astronomer, Claudius Ptolemy, writing in the 2nd century ad, mentions both ports by name, but curiously does not refer to the city of Thera. The finds from the Geometric and Archaic cemeteries of the city show that Thera knew considerable prosperity early on. Herodotus recounts that, after a protracted drought of several years around 630 bc, the city was forced to found a colony of its own at Cyrene on the north African coast. This was its only colony, but one which grew to unforeseen wealth and importance. Thera, as was typical of Dorian settlements, was conservative both in its art and its external relations. It only be came a truly cosmopolitan centre in Hellenistic times under the rule of the Ptolemies. It is from this period of prosperity that most of the visible ruins and the plan of the city date.
The site was first examined and the cemeteries excavated by the German scholar, Hiller von Gi¤rtringen, between 1895 and 1903. The next systematic excavation was begun by Greek archaeologists under nikolaos Zapheiropoulos in the 1960s, and continues today.
Santorini Island is part of the Cyclades Island Group, Greece.