At Pevensey, William built a castle inside the ruins of a Roman fort.
The earlier fort was the late Roman Saxon Shore fort known as Anderitum, built around 290 AD. By the time of the Norman invasion it had fallen into ruin, but its massive walls and strategic position near the coast made it an ideal defensive site.
William’s army landed at Pevensey Bay on 28 September 1066 and used the old Roman fort as a temporary stronghold. The Normans repaired parts of the Roman walls and dug additional defences before moving toward Hastings. A more permanent Norman castle was developed within the Roman enclosure, probably during the 1070s under Robert, Count of Mortain.
The site therefore combines three historical layers: a Roman coastal fort, a Norman castle, and later medieval military occupations. It is not evidence of a Norman abbey, Viking camp, or Saxon hall. The castle’s surviving outer walls are largely Roman in origin, though altered and repaired over many centuries.