The Normans took Cumberland in 1092, when William II — William Rufus, son of the Conqueror — pushed his northern frontier into what is now western Cumbria. The original castle at Egremont went up on a mound above the River Ehen, on the site of an earlier Danish fort. The motte-and-bailey design was the classic Norman tool of conquest: a raised earthwork crowned by a wooden keep, with a fortified yard below. The present stone castle was the work of William Meschin, who built it between 1120 and 1135 during the troubled reign of Henry I. Meschin made it the seat of a substantial estate. Further additions came in the 13th century, when stone curtain walls and improved towers replaced the earlier timber and rubble. Eventually it fell into disuse and weathered down to the ruins still visible today.

Meschin did not just build a castle. He laid out the town of Egremont beneath it as part of the same design. The long, wide main street — still the spine of the town — was set out as a marketplace for traders, who in return for paying tolls received privileges and the security of the castle's garrison. Medieval lords often founded boroughs as ways of monetising peace; people would pay to live and trade somewhere where they would not be robbed by the next minor lord down the road. Some of the profits from Egremont's tolls almost certainly funded another of William Meschin's projects: the foundation of St Bees Priory, a few miles down the Cumbrian coast, dedicated to Saint Bega — the Irish princess and saint whose name still marks the headland and beach where her relics were once kept. Castle, town, priory: a Norman lord's three-part installation in a freshly conquered land.

Egremont below the castle is still a working market town, and its annual Crab Fair — granted a royal charter in 1267 by Henry III — is one of the oldest fairs in England. It is famous for the World Gurning Championships, in which competitors pull faces through a horse collar; the events draw photographers and television crews each September. The castle itself has a quieter life. It became a Grade I listed building, a recognised national treasure of medieval military architecture, viewable from the town below. In 1986 an idealised image of Egremont Castle, painted as if mid-creation on an artist's easel, appeared on the cover of The Big Lad in the Windmill, the debut album by the band It Bites. Three of the four members had grown up in Egremont. The album's lead single, Calling All the Heroes, reached number 6 on the UK chart that summer — a Norman castle on the cover of a 1980s prog-pop record, which is the kind of cultural cross-section only a small English town ever produces.

Egremont sits between the Lake District fells and the Cumbrian coast — between the Scafell range to the east and the Irish Sea to the west, with Sellafield's gleam visible from certain headlands. The castle's red sandstone walls weather into deep colours in evening light. The history is full of fighting men whose names did not survive — soldiers who stood watch on these walls during the long centuries of the Anglo-Scottish wars, when a Border raid could appear from the hills any night; masons who quarried the local sandstone; smiths who shoed the lord's horses. None of them got into Wordsworth's poem, but they built and held and rebuilt what we still see. The motte beneath the castle stones is older than the Normans who shaped it. The Danes had used the spot first, as they used so many high points in Cumbria, and the soil beneath the ramparts still holds whatever they left behind.