Syros (Greek: Σύρος), or Siros or Syra is a Greek island in the Cyclades, in the Aegean Sea.
The largest towns are Ermoupoli, Ano Syros, and Vari (el). Ermoupoli is the capital of the island and of the Cyclades. It has always been a significant port town, and during the 19th century it was even more significant than Piraeus. Other villages are Galissas, Foinikas, Pagos, Manna, Kini and Poseidonia.
The history of settlement on Syros goes back at least 5,000 years, to the Early Bronze Age of the Cycladic civilization. This is when the hill-top settlement of Kastri (Syros) began. Archaeologists describe Early Cycladic III (ECIII) culture as Kastri culture.
Kastri, dated by archaeologists to 2800-2300 BC, was one of the earliest settlements in Greece that were protected by stone walls with rounded bastions. Also the cemetery of Chalandriani is associated with Kastri. Inside the fortification, the houses shared party walls and were packed close together.
The site was first discovered and excavated in 1898 by Christos Tsountas, the “father of Cycladic research”. Kastri had some of the earliest metalwork in the region, and also some of the earliest use of potter’s wheel.
Throughout history, the island was knowns as Syra, then Syros or Siros. In later times, it appears to have been inhabited by the Phoenicians. In the Odyssey, Syros was the country of the swineherd Eumaeus who described it at length (Odyssey, XV, 403 sq.).
The island was also the home of the philosopher Pherecydes, the teacher of Pythagoras. It possessed two leading cities, Syros (now the modern Ermoupoli) and another city on the western coast where stands to-day Galissas.
The island did not play an important role during antiquity nor the early Christian years, it was not even a diocese at a time when even the smallest island possessed its bishop. During Roman times the capital of Syros was situated in the area of contemporary Ermoupoli.
At the end of ancient times, the barbarian raids and piracy, which had surged the Aegean for many centuries, led Syros to decline. The island, along with the other Cyclades, was devastated several times during the Middle Ages by raiders from different directions including Sicilians, Arabs, Turks, and Venetians.
In the Byzantine years Syros constituted part of the Aegean Dominion, along with the rest of the Cycladic islands. After the overthrow of the Byzantium in the Fourth Crusade by the Venetians and Franks in 1204, was definitively conquered by the Venetians under the leadership of Marco Sanudo and as part of the Duchy of the Archipelago, Syros would remain under Venetian rule until 1522.
It was at this time that Ano Syros was founded. During the Latin period, the majority of the local community were Roman Catholics, but maintained the Greek language. During the reign of almost three and a half centuries of the Duchy of the Archipelago, Syros had a singular feudal regime.