Isidore in the Well

Christianity reached Chios early, carried along the same sea-lanes as the wine and the resin. The island claims a visit from St Paul; the Acts of the Apostles records that on the voyage from Troas toward Jerusalem the ship "came the following day opposite Chios," which is not quite a visit, but has been treated as one for nineteen centuries and there is no harm in it.

The island's own saint is Isidore, and his story is the one that took root.

He was, according to his passion, an officer or seaman in the Roman fleet, of Alexandrian origin, serving in a squadron that put into Chios during the persecution under the emperor Decius, around AD 250. A shipmate denounced him. Brought before the commander, he refused to sacrifice; he was tortured, dragged behind horses along the road, and beheaded, and his body was thrown into a well. From the well, the tradition holds, a spring of healing water rose.

A basilica was built over the site, and the cult of St Isidore remains one of the island's principal devotions. His relics, like so many Aegean relics, ended up in Venice, where they lie in a chapel of St Mark's — carried off in the Middle Ages by the most acquisitive city in Christendom, whose basilica is, among other things, a museum of what Venice took from other people's islands.

The island's other great saint is much later and rests on almost no evidence at all, which has done nothing to reduce her hold. St Markella is venerated at the north-western tip of the island near Volissos, and her legend is folkloric to its core: a young woman pursued by her own father, fleeing to the shore, praying, and the rock opening to receive her so that only her head remained visible when he struck. The sea at the site is said to be warm, and to boil. Pilgrims come in their thousands in July. The historical content is nil and the devotion is immense, and anyone who wants to understand a Greek island should spend an afternoon at Agia Markella watching families arrive, light candles, take water home in plastic bottles, and eat lunch on the beach.

Institutionally, Chios through the Byzantine centuries was a bishopric under the metropolitan of Ephesus and eventually a metropolitan see in its own right, and its economic life continued much as before; mastic remained in demand and Byzantine sources refer to it. But politically the seventh to ninth centuries were miserable. The Arab naval offensives that followed the rise of Islam turned the Aegean into a war zone; Chios was raided repeatedly from the seventh century, and after the establishment of an Arab emirate on Crete in the 820s, Cretan corsairs made the whole sea dangerous for a century and a half. Coastal settlements shrank or moved inland or disappeared. The tendency of Chian villages to sit in folds of the hills, out of sight of the water, dates in significant part from this era, and it is a pattern that repeats across the Aegean: you can read three centuries of insecurity off a map of where people chose to live.

The Byzantine recovery of the tenth century — the reconquest of Crete by Nikephoros Phokas in 961, and the reassertion of imperial naval control — restored security to the islands. Chios was organised within the theme system, its economy revived, and in the middle of the eleventh century, in a period of unusual calm and imperial generosity, it received the building that remains its greatest monument.