Worlebury
(From Mr Hadrian Allcroft’s Earthwork of England, by kind permission of Messrs Macmillan & Co.)
It has often been argued that these prehistoric fortresses were merely places of refuge, to which, in time of war, the dwellers in the levels below betook themselves and their flocks. But it is much more probable that they were the permanent habitations of communities, not merely camps, but fixed settlements, chosen for habitation on account of their strong position, and gradually fortified by labour which may have been the work, in the more elaborate examples, of many generations. The need of permanent protection for themselves and their flocks and herds seems to have been felt by the early inhabitants of Britain to such an extent that their regular settlements naturally took the semblance of fortified camps. This is very evident in the case of those camps which are found in positions where the natural advantages are very small—positions which might be chosen by people in search of an abode, but would hardly be chosen merely as a refuge. Camps in these positions are never so imposing as those which crown hill-tops: the labour of excavating the ditches and heaping up the banks was not aided by the natural slope of a hill, and the earthworks, being slighter and nearer the more recent haunts of men, are more liable to destruction. But the defensive nature of such settlements is unmistakable.
The Roman invaders brought to England new methods of military construction and the tradition of an architecture of dressed and cemented stone. Their whole system of warfare was far in advance of that pursued by the British tribes. They had developed the art of siege to a high pitch. Their operations in open field were orderly and scientific. Their walled strongholds were constructed with a view which took into account, not only the mere strength of the ramparts, but also the capacity of the defenders to man them. Men, not fortresses, were the main asset of Roman warfare; and consequently their earthwork was far less imposing than that of the Britons of the prehistoric age. Their camps and permanent stations were usually surrounded by a single fosse of no great depth: the rare cases in which traces remain of more than a single fosse are camps upon the exposed northern frontier of Roman Britain, where the onrush of the barbarian enemy was stayed by a series of trenches, either covered with brushwood or filled with sharp stones or stakes. Camps were hastily constructed of earthwork; bank, ditch, and parapet playing their part. But where a camp became a permanent station a stone wall took the place of the earthen bank. The most important relic of the Roman occupation in Britain, the great frontier wall from the Tyne to the Solway, was preceded by a vallum of turf, a temporary defence which was superseded by permanent masonry.
No system of connected operations can be traced between prehistoric forts. Each of these was probably an isolated stronghold. Roman stations, on the other hand, were military posts manned by detachments of one army, and connected by strategic roads. This is seen very clearly in the case of the great wall already mentioned. The wall can be traced for about 73 miles, from Wallsend (Segedunum) on the Tyne to Bowness on the Solway. It is built in the usual Roman method, with a core of cemented rubble between ashlar facings. Its breadth varies between 7 and 9½ feet: the height appears to have been originally from 16 to 18 feet.[6] Its northern face is defended by a ditch, marked a in the section below; but, as it follows the highest ground in its course, and runs for some distance along the edge of basaltic cliffs which dip northward, the ditch at these points becomes unnecessary and is dispensed with. There were twenty-three stations in its length, each garrisoned by a cohort of infantry or squadron of cavalry, chosen from the Roman auxiliary troops of Gauls, Spaniards, Moors, &c.[7] These were connected by a paved military road (c) along the south side of the wall. At distances of a Roman mile from one another were placed rectangular forts, now known as mile-castles, built against the wall upon its south side; and the interval between each of these was strengthened further by turrets, apparently two in number, which also projected southward, but encroached slightly upon the thickness of the wall. The south side of the military road was defended by an earthen vallum, marked d,[8] the course of which is not directly parallel to the wall, but is in places as much as half a mile distant, keeping to lower ground where the wall prefers the summit of the basalt ridge. This bank has a ditch (e) on its southern side, divided from it by a level space or berm: the ditch has a southern parapet (f), and another bank beyond (g). In certain places the ditch has also a northern parapet; but the general arrangement of the earthen ramparts is as described. Of the controversy as to the relative date of the wall and its flanking earthworks nothing need be said here. Its military purpose is abundantly clear. It provided not only a strong means of defence against the attacks of the northern tribes, but a base of operations for offensive warfare. Each of the stations and mile-castles has a northern gateway in addition to its other entrances; and two of the Roman roads which met the wall at intervals from the south passed through it on their way to the Scottish border.
Section of Roman Wall and Vallum.
The object of the great system of Roman roads was purely military.[9] Along these broad paved “streets” the troops from the various stations could be mobilised with great quickness. They kept as a rule to high ground, choosing a convenient ridge, like that which runs from end to end of Lincolnshire, and preserving as straight a line as possible. The most important stations were placed at the crossing of rivers or at the junction of roads. In the early days of the Roman occupation, the operations of the army were directed entirely against the native tribes. No system of coast defence was adopted. The necessity for this came later, when Britain, under Roman dominion, was attacked by bodies of Saxon pirates. A chain of fortresses was then constructed along what was known as the Saxon shore, from Branodunum (Brancaster) in north Norfolk to Portus Adurni in Sussex or Hampshire. The remains of the walls of Gariannonum (Burgh Castle in Suffolk), Rutupiae (Richborough in Kent), Anderida (Pevensey in Sussex), and Portus Magnus (Porchester in Hampshire), are, next to the great wall, perhaps the most interesting relics of the Roman epoch which we possess. The forts of the Saxon shore were placed, for the most part, at the mouths of estuaries, for which the foreign pirates would naturally make.