Excavations of an Early Cycladic fortified settlement and burial ground at Kastri in the island’s northeast date from the Neolithic era (2800–2300 BC).

During the 17th and 18th centuries, Capuchin monks and Jesuits settled on the island. Becoming overwhelmingly Catholic, Syros even called upon France for help during Turkish rule.

During the War of Independence, thousands of Orthodox refugees from islands ravaged by the Turks fled to Syros. They brought an infusion of Greek Orthodoxy and a fresh entrepreneurial drive that made Syros the commercial, naval and cultural centre of Greece during the 19th century. Syros’ position declined in the 20th century, but you still see shipyards, textile manufacturing, thriving horticulture, a sizeable administrative sector, a university campus and a continuing Catholic population.