Dikes

In contrast to the wide range of fortifications in the preceding Roman and succeeding medieval periods, not a lot is known of fortifications in Britain during the centuries of the Early Middle Ages (c. A. d. 410-1066, roughly from the departure of the Romans until the Norman conquest), a period sometimes designated by the rather negative term of Dark Ages. In order to investigate Dark Age fortifications in Britain we are stepping into a region of doubt and obscurity. Historical sources available for this period are rather scanty. But for the Anglo-Saxon Chronicle, there is little written evidence from this time and much of what we know from the early written sources was actually transcribed much later. The Venerable Bede’s Historica Ecclesiastica writings, for example, which provide us with the most complete account of the history of this period, date from the mid-7th century. These writings are by monks who had no interest in military matters and no comprehension of strategy, tactics or fortifications. Thus the topics of military architecture in Dark Age Britain remains somewhat unclear, and no precise conclusions may be drawn with certainty. It is fortunate, however, that the general characteristics of the period render its military architecture comparatively simple. Of sophisticated strategy there could be little in an age when men strove to win their ends by hard fighting rather than by skillful operations or the use of extraneous advantages.

The centuries of the Dark Ages, however, saw the gradual evolution of new forms of warlike efficiency whose result was—out of necessity — the establishment of a mounted military class as the chief factor in warfare. In the absence of any centrally organized resistance, the defense fell into the hands of the local nobility, whose members became semi-independent sovereigns. To these petty rulers the landholders of each district now commended themselves, in order to obtain protection in an age of insecurity and anarchy. At the same time, and for the same reason, the poorer freemen were commending themselves to the landholders. Thus the feudal hierarchy was established, and a new military system appeared, when counts, dukes and earls led out to battle their vassals and their mounted retainers.

It seems that the Angles, Saxons and Jutes had their own military fortifications, which fall into two main categories: linear works, known as dikes, and burhs (fortified towns). Burhs, described separately below, actually belong to the last two centuries before the Norman conquest of 1066, leaving only dikes to fill the four centuries between a. d. 410 and c. a. d. 800.

While fortifications were not unknown to the Anglo-Saxons, battles tended to be in the open. Many of the conflicts in Dark Age Britain were followed by some sort of treaty or oral agreement, whereby one side or the other promised to keep within its own territories. This is probably the origin of linear earthworks, emphatic and remarkable expressions of territoriality, some still featuring in the British landscape.

Wansdike

Wansdike is a rather enigmatic and unknown Dark Age dike, consisting of two main linear earthworks; the piece that is believed to have connected the two pieces is now known to be a Roman road, which is 15 miles (22 km) long. The western half extends nine miles from Dundry Hill southeast of Bristol to just south of Bath. The eastern half runs ten miles from south of Calne to Great Bedwyn on the edge of Sav-ernake Forest. Presumably built at different times from the 5th to the 7th century A. D., the line includes a ditch and rampart some 25 meters in total width and 7.5 meters from the bottom of the trench to the top of the bank. Two Iron Age hill forts along the western part of the Wansdike have been incorporated into its structure (Stantonbury and Maes Knoll) and some scholars have concluded that the builders used the hill forts to save on labor. But as the builders did not refortify the forts, garisson them or patrol the dike (apparently a walkway on top of the ramparts was not built), it is now believed that the Wansdike was simply an expression of territoriality, a kind of border marker. Both sections run along an east/west line, with the ditch facing north, and scholars disagree not only about its precise location but also as to whether the dike was built by the Romano-British Celts as a defense against Saxons encroaching from the upper Thames valley westward into what is now the West Country, or, if later constructed, by the Saxons of Wessex against their rival Saxons in the Midlands.

Offa’s Dike

Of greater renown and more precise dating is Offa’s Dike, a massive linear earthwork, roughly following some of the current border between England and Wales. The origins of the Dike are, however, shrouded in mystery, so many of its aspects are speculated upon rather than being fully understood. It has been claimed that it was built by the Emperor Septimus Severus about A. D. 200, but this is probably incorrect as the sources of the story of Severus building a turf wall in Britain are probably confused references to him rebuilding the Antonine Wall. Severus fought against the Picts in the north, and refurbished the Antonine Wall, and he would have had no reason for building a barrier in the western part of Britannia. It was Asser, King Alfred’s friend and biographer, in the 9th century who first ascribed the dike to Offa. It is now generally accepted that much of the earthwork can indeed be attributed to Offa, king of Mercia from a. d. 757 to 796. By that time Mercia was the dominant power in England south of the River Humber, and Offa was recognized in Europe as virtually king of the whole country as he had influence in international affairs, links with the Papacy, and diplomatic contacts on more or less equal terms with the Car-olingian Frankish Emperor Charlemagne, the most powerful continental European ruler. Offa influenced the setting up of a third archbishopric in England at the cathedral at Lichfield and near his principal residence at Tamworth. He established the use of the penny as the standard monetary unit in England, with the same silver content as coins in circulation in the European Carolingian Empire, thereby assisting both national and international trading. Offa’s kingdom covered the area between the Trent/Mersey Rivers in the north to the Thames valley in the south, and from the Welch border in the west to the Fens in the east. At the height of his power Offa also controlled Kent, East Anglia, and Lindsay (Lincoln). He also had alliances with Northumbria and Wessex, sealed by the marriage of two of his daughters to their kings, Aethelred and Beorhtric, respectively. Offa was, therefore, effectively an early king of England.

The earthwork that bears his name ran from Prestatyn on the northern Wales coast to Cheptow on the River Severn in the south, a length of about 120 miles. The “dike,” today a mere raised hedgerow and small earth mounds, then consisted of a continuous bank fronted by a ditch about 50 feet wide, in places, up to 65 feet (20 m) wide (including its surrounding ditch) and 8 feet (2.5 m) high. In certain sections the Severn and the Wye Rivers were use instead of a wall. How Offa’s dike (and other linear earthworks) functioned as military structures (or even if they were military structures at all) is open to debate. Some sections may have been garrisoned and patrolled in some unknown periods, but the dike was probably a purely symbolic border between places where the movement of goods was controlled (like the Salt Tax Hedge in India, a purely economic border between two areas, both under British control, showing that a barrier does not have necessarily a military purpose). The fact is that Offa’s Dike could not possibly have been permanently manned, as the Mercian realm could hardly afford to maintain a permanent army. Besides, there is no evidence of fortified accommodation such as milecastles, interval towers and forts for a supporting garrison as on the Roman Hadrian’s Wall. Obviously this thin line would not have prevented infiltration; it would never have repulsed or slowed down a gang of raiders, let alone an army. So it was not a proper line of fortification, but presumably the result of negotiation rather than conquest. However, the construction of such a work was clearly a considerable undertaking and an impressive tribute to Offa’s prestige. In the 8th century the dike expressed Offa’s power, and formed a physical frontier delineating the Anglian kingdom of Mercia and the Celtic Welsh kingdoms of Gwynedd, Powys and Gwent. The provision of a visible frontier secured the stability of disputed territory, and Offa’s Dike marked a border and constituted a clear warning for Welsh intruders that beyond that line they were risking retribution from the Mercians.

The upper hand enjoyed by the Mercians did not long survive Offa’s death. In the 820s a series of victories by Egbert, king of Wessex, broke Mercian control in the southeast. The 9 th century may well have turned into a struggle for the upper hand between Mercia and Wessex if not for one thing: England was once again the subject of recurring raids from across the seas. This time it was the Danes and Norwegians, as said above. The Danes attacked the east coast of England, and the Norwegians attacked the north by way of Ireland and Scotland.

Wat’s Dike

Another much less famous linear work was so-called Wat’s Dike, an earth wall and ditch running more or less parallel to, and to the east of, the northern part of

Offa’s Dike through the northern Welsh Marches from Basingwerk Abbey on the River Dee estuary, passing to the east of Oswestry and onto Maesbury in Shropshire, a distance of approximately 40 miles (64 km). The dating of the earth wall has been disputed. Some scholars dated it to between a. d. 411 and 561 (centered around a. d. 446), placing the building in the post-Roman era. Others think the dike formed part of the late Roman attempts to counter “barbarian” attacks (i. e., Pictish and Irish) in

Wansdyke today (near Spye Park).

Offa’s Dike today (near Spring Hill, Shropshire).

The region of modern North Wales. The consensus view now places the date of construction in the early 8th century by Aethelbald, king of Mercia, who reigned from 716 to 757. Aethelbald was the predecessor of King Offa of Mercia, and his (uncompleted) work was intended to perform the same function as his successor’s: a physical mark of the frontier of his realm. For centuries, both dikes had a cultural significance, symbolizing the separation between the English and the Welsh, similar to the symbolism of Hadrian’s Wall between England and Scotland. Crossing these lines with drawn sword corresponded to handing over an official declaration of war in more literate eras.

Ojfa’s Dike

There are several other notable linear earthworks in Britain, notably the Bokerly Dike on the Dorset/Hampshire border. The Devil’s Dike in Cambridgeshire, with a length of 9 miles and a well-preserved section between Swaffham Prior and Stetchworth, is thought to have been built between A. D. 500-600 by the East Anglian Saxons to block attacks from Mercians to the west.

The rash of dike building in Britain in the early part of the Dark Ages may have been initially inspired by the Roman practice of building physical border limes, as Hadrian’s Wall. But these enigmatic linear structures have not yet revealed all their secrets about this period of British history.