Samos was initially inhabited by Phoenicians and Minoan Cretans. In 5th century Persians conquered the island and later it was liberated by Athenians. Siros was dominated by Macedonians, Ptolemie kings of Egypt and Romans.

Siros was part of the Eastern Empire (Romania), until the fall of Constantinople in 1204, when venetian Marco Sanudo became ruler of the island. In 1537, Turks conquered Siros. They respected the inhabitants because they had become catholics. Turks were ruthless only to Orthodox Christians.

During the Greek Revolution of 1821, Syros did not participate in the war for independence and Turks never landed to the island. This fact saved many refuges from Psara, Chios, Cydonies of Minor Asia who found refuge and founded the city of Ermoupolis. The capital, since 1832 and until the end of 19th century had a great development, became an important commercial and industrial centre. The shipyards were famous in all mediterranean sea. This economic development lasted until 1900's.