Syros was the largest cultural and trade centre of the Agean in the 19th century and capital Ermoupolis was Greece's principal port. From the time of the Fourth Crusade (13th Century) until 1568 Syros belonged to the Duchy of Naxos.

After that period the island had a significant Roman Catholic minority which was under the protection protection of France from piracy and the during Turkish occupation. For this reason the island remained neutral during the War of Independence and people from other islands who escaped massacres found refuge in Syros and built the island's capital - Ermoupolis- between the district of Ano Syros and the seafront.