Hermoúpolis, chief port of the island of Syros (part of the Cyclades group in the Aegean Sea), South Aegean (Modern Greek: Nótio Aigaío) periféreia (region), southeastern Greece. The seat of both a Greek Orthodox and a Roman Catholic archbishopric, it was founded in 1821 at the beginning of the War of Greek Independence by Greek refugees from Psará and Chios. The city’s classical-revival architecture reflects its former importance as a Greek trading centre. The Catholic quarter, Áno (Upper) Síros, on the south hill, has many descendants of the Venetian and Genoan 13th-century settlers who remained under the Turks with protection from the kings of France. On the north hill is the Greek Orthodox quarter, Vrontado. Still the most active port in the Cyclades, Hermoúpolis has dry-dock facilities, ironworks, cotton mills, and tanning industries. Pop. (2001) 11,938; (2011) 11,407.