Anderitum

Anderitum (also Anderida, Anderidos) is a Saxon Shore Fort in the Roman province of Britannia. It is located at in eastern Pevensey in the English county of East Sussex and was later converted into a medieval castle known as Pevensey Castle.

Roman fort
It was built by the Romans during a time when Britain was still part of the Roman Empire. Recent dendrochronological dating of wooden foundation piles have dated this to AD 290. It used to be customary to state that at this time the south and east of the province Britannia were under constant attack from marauding barbarian Jutes and Saxons, but more recent thinking focuses on the internal disputes of the Roman Empire in that period. The south and eastern seaboards of Britannia were collectively known as 'the Saxon Shore' and several large forts were built along them.

The fort was built on what was then peninsula of land rising above the coastal marshes. The sea washed over what is now Pevensey Marshes surrounding Anderida on three sides, so giving a safe and sheltered landing point. This marshy inlet of the sea, extending inland as far as Hailsham, was studded with small areas of high land which remained as islands at high tide so giving the place-names of Rickney, Horse Eye, North Eye and Pevensey. All are derived from the Old English word īeg, meaning island.

The Roman road leading west away from the fort was built much earlier than the fort itself. There was probably a port already in existence in the area when the fort was built, though this has yet to be found.

The fort was repaired, possibly on the instructions of the great Roman General Stilicho, about AD 400. The massive Roman enceinte still stands but little damaged.

Saxon fort
The sub-Roman Brythons apparently occupied the fort in 491, though whether this was part of a long term residency or a temporary one necessitated by Saxon raids is unclear. The Anglo-Saxon Chronicle records that they were massacred there, at Andredesceaster, by King Ælle of Sussex and his son Cissa in that year, leaving none alive.

The site was next occupied in 1042, when the Anglo-Saxon Earl of Wessex, Harold Godwinson (later King Harold II) established a strong point here, improving fortifications by digging ditches within the walls of the Roman fort. The English army remained at the fort during the summer of 1066 before abandoning it to meet the invading Norwegians further north.

Later castle
After the Saxon defeat at the Battle of Hastings, the Normans briefly used the fort as a temporary camp before it was converted into a castle around 1100. Occupation continued until the Elizabethan era.