The pronunciation is contested even among the people who live here. Locally, many call it "cly," rhyming with spy, and the village's own website agrees. Scholars argue for "clay," rhyming with day, because the name descends from the Anglo-Saxon claeg, meaning clay, and the Domesday Book of 1086 spelled it Claia. Peter Trudgill, the linguist who grew up in nearby Norwich, makes the case in his book Dialect Matters: the Old English word daeg became modern day, so claeg should become clay. The locals nod, smile, and carry on saying cly. A village that lost its sea over four centuries is in no hurry to be corrected on its name.

In 1612 fire tore through 117 buildings in Cley, and the village rebuilt itself in the architectural fashion of the day. That fashion was shaped by trade. Norfolk merchants ran ships back and forth across the North Sea to the Low Countries, and the masons borrowed the stepped Flemish gable they saw across the water. The result is a small village dense with continental flourishes, marooned in the English countryside. Cley Windmill, built later in the 1700s, became its emblem. The Blunt family, including the singer James Blunt, owned it for decades and ran it as a bed and breakfast; it appeared as a backdrop in the 1949 Elizabeth Taylor film Conspirator, and Rowland Hilder painted it into the canon of English landscape. The mill still hosts overnight guests beside the reeds.

In early August 1914 the poet Rupert Brooke was staying in Cley with the classicist Francis Cornford and his wife Frances, herself a poet. The news that Britain had entered the war reached the village while Brooke was there. He had dreamt the war the night before and woke to find the dream had become real. He did not speak to his hosts all day. Eventually Frances broke the silence: "But Rupert, you won't have to fight?" Brooke answered, "We shall all have to fight." Brooke died on a hospital ship off the Greek island of Skyros the following spring. A generation later, mortar pits, slit trenches and bunkers went up around the village against a different threatened invasion.

The Norfolk Wildlife Trust took on the marshes in 1926, making Cley Marshes the oldest county Wildlife Trust reserve in Britain. The location is geographically lucky: the apex of the North Norfolk coast is a natural funnel for migrating birds, and the marshes attract avocets, bearded tits, bitterns, marsh harriers and spoonbills among the breeding population, with brent geese, wigeon and pintail arriving for the winter. The eco-friendly visitor centre opened in 2007 looks across reed beds toward a sea that increasingly threatens to take them. The shingle ridge that protected the marshes was largely destroyed in the 1953 North Sea flood, and the Environment Agency has openly raised the prospect of managed retreat. The yellow horned poppies still bloom on the shingle, for now.

Up on Cley Green stands St Margaret's, Grade I listed, dedicated to Margaret of Antioch. The mercantile de Vaux family paid for it in the 14th century and the mason William de Ramsey began the work, only to have construction halted by the Black Death sweeping through East Anglia. The church still carries the scars of that interrupted ambition: carved roundels, an elaborate medieval font, and a damaged set of royal arms from the reign of Queen Anne. Down by the marshes, a ruined building known as Blakeney Chapel stands in Cley parish despite its name and was probably never religious at all. Archaeologists now believe it was an iron smeltery.