Roman Fortifications

Originally referring to a temporary marching camp, castra became the definitive term for permanent, large-scale military bases. These housed full legions of around 5,000 to 6,000 men, or large auxiliary regiments of comparable strength. They were essentially stone or turf cities, complete with standard internal grids, a headquarters building (principia), the commander's house (praetorium), granaries, and bathhouses. In England, castrum/castra became the source of place name elements such as caister, caistor, caster, castor, cester, chester and eter, derived via the Saxon cæster, typically indicating a major Roman fort together with its surrounding vicus (supporting town). British examples include Chester (Deva), York (Eboracum), and Caerleon (Isca).

Place names beginning with Castle- generally derive from castellum, while names ending in -castle are more typically of Norman origin — though this is a tendency rather than a hard rule. The Saxons appear to have adopted the word freely as a general term for any visible Roman fortification, which makes precise attribution difficult. A further complication is that the Normans themselves often planted their castles on or immediately adjacent to existing Roman defensive positions. Bodiam Castle is a likely example of this pattern — sited to control the northern bank of the Rother, commanding both the causeway crossing of Margary 13 and the approach to the extensive iron-working complex of the Brede valley.

The term burgus, derived from a Germanic or Greek loanword, became prominent in the Late Roman Empire of the 3rd and 4th centuries AD. Much smaller than a castellum, a burgus was a compact, heavily fortified outpost — typically a stout central tower enclosed by a fortified wall and ditch.

They were explicitly logistical and defensive nodes, built along vital riverways, estuaries, and major highways. They did not house armies; instead small detachments of guards (burgarii) secured supply depots, collected taxes, protected river crossings, and kept heavy freight moving safely through difficult terrain such as the Andredsweald. A specialised variant, the burgus with river landing (Ländeburgus), incorporated crenellated walls extending to the riverbank like pincers, protecting a berthing bay for cargo ships and patrol boats — a pattern potentially relevant to the Cadborough location near Rye, at the strategic head of the River Brede.

The modern place name element Borough derives from burgus; the distinct elements Burgh and Burg could derive from Burgus but may derive instead from the Saxon beorg, meaning a hill.

It would seem that four distinct Latin terms were used for Roman military sites, broadly implying a hierarchy of size and function:

• Castra — large permanent bases for legions or major auxiliary units
• Castellum — smaller auxiliary forts housing cohorts or cavalry wings, forming the backbone of road and frontier control
• Burgus — compact late-Roman fortified posts, typically logistical in function, guarding river crossings, supply routes and tax points
• Specula / Turris — timber or stone watchtowers spaced at approximately Roman mile intervals for signalling and early warning

In our area of East Sussex, full castra are rare. Hastings Ceastre, mentioned in the Burghal Hidage, preserves a Roman place name even if the Saxon-period record is later, and the fort of Anderida at Pevensey is the clearest surviving example.

We have identified only one likely burgus — at Cadborough Cliffs near Rye, at the strategic mouth of the River Brede. Its position controlling river access makes it a strong candidate for a Ländeburgus of the type illustrated above at Burgus Zullstein.

Possible castellum locations survive in place names beginning with Castle- — Castleham being a slight variation — typically in strategic positions on or near major Roman roads. These may represent more substantial, possibly stone-built structures that coordinated the surrounding watchtower network.

The watchtowers themselves would have been timber-built, drawing on the vast resources of the Andredsweald. Although no surface traces survive, their surrounding ditches may still be detectable on LiDAR.

One further point of interest: the Romans referred to the River Rother as the Limen. In Saxon this could derive from lǽmen meaning "earthen," but a more compelling possibility is that it preserves the Latin directly — limen meaning "threshold" or "boundary of the military zone." The related Latin limes carries the same sense of limit or frontier, raising the intriguing possibility that the Rother itself functioned as a formal limes — a recognised military boundary of Roman Britannia.