The most remarkable monument of Roman engineering in the Fens is the catchwater drain called the Cardyke (Brit. “fen-dyke”), which leaves the Witham at Washingborough about three miles from Lincoln, and then for eighteen miles takes a southerly course parallel to that river at distances varying from two to five miles from it. The primary object may have been to intercept the water of the numerous streams coming from the Kesteven uplands; but it was doubtless intended to be navigable, as its width at the water-level was 50 feet, and at its bottom 30 feet. On both sides was a raised bank, flattened at the top to serve the purpose of a road, and still in some places crowned with a modern road. In the parish of Heckington, nine miles due west of Boston, it makes a sharp turn to the south-west, and then skirts the western border of the Fen for over thirty miles, till, after a course of fifty-six miles, it joins the river Nene, half a mile south-east of Peterborough, and about five miles below the Roman town of Durobrivæ (Castor). In some parts the Cardyke has been obliterated, and in many it is now a mere ditch; but its whole course can be exactly traced, and for a few miles it is still used as a drain. The last eight miles are beyond the borders of our county; but within those borders Roman remains have been found in at least ten parishes through which it passes. No vestiges can be found of the seven forts alleged by Stukeley to have been raised along its course, but there is a camp at North Kyme, within a short distance. Even with the aid of forced labour—partly, perhaps, imported from the Continent—such a work must have taken many years to construct; and it may have been in progress during a great part of the century between Trajan and Severus (A.D. 100-210). Its long course, parallel to the canalised channel of the Witham, suggests that its northern portion was first undertaken to assist in draining the mere south-east of Lincoln. But when this object was accomplished, and the immense work was taken in hand of embanking the shores of the Wash, the canal would gradually be extended southward in order to provide an inland waterway past Lincoln, by the Fossdyke, the Trent, and the Ouse, to the northern capital at York. This measure could hardly have been contemplated until the Holland Fen was sufficiently dry to admit of causeways being made across it into Lindsey on the north and Norfolk on the east.
The seabanks in Holland and East Lindsey, which are now called the “Roman Banks,” extend by a most circuitous route for about a hundred and fifty miles from Wisbech nearly to Grimsby. Tradition ascribes them to the Romans; and as their bases are deeply buried in silt, they are evidently of pre-Norman origin. Mr. Skertchly has estimated that at least eleven million tons of material must have been used in their construction. His collaborator, Mr. Miller,[21] suggests that this stupendous work may have been partly executed before the Roman invasion. But as this idea rests upon two very uncertain conjectures—(1) that the Coritani were Germans from the Low Countries with a knowledge of embanking, and (2) that they may have learnt engineering from the Greek colonies in Gaul, it may be dismissed as improbable. The tribal natives, whatever their state of civilisation, could hardly do more than provide a core of clay, upon which the banks of blown sand could gradually form. It has been well pointed out that the Roman Banks are not works of such a kind as could be carried out in portions, and spread over a number of years.[22] “The enclosure of a large tract covered by the spring-tides is a work that requires great vigour, and must be carried on continuously, or the earth put into the bank during one set of tides will be washed away again.” That is to say, it is a work which would require a strong, and even despotic, central authority. In the fen south of Boston there is a succession of about twenty tumuli, called the Fen Mounds, which are all within about three miles of the ancient banks, and some of which are called “toot” (or “look-out”) hills. They have been supposed to be British,[23] but only one of this southern series is crowned with a circular entrenchment, and it seems much more likely that they were raised to protect the bankmakers from a surprise attack.
The Romans do not seem to have reaped much fruit from their labours, except perhaps in the complete pacification of the district. Holland affords but few traces of their settlement, except in pottery and coins found along the line of the banks, as at Holbeach, Fleet, Heckington, and Swineshead. There was an important oblong camp on the Witham at Redstone Gowt, about a furlong south of Boston, where remains have been found. Its importance was due to the two circumstances that here was a ferry in connection with the road called the Saltway into the Midlands, and that at this point a canal, now called the Old Hammond Beck, took over some of the Witham water due west round the end of Bicker Haven to Swineshead, and thence, taking a sharp curve, after a southerly course of thirteen miles, fell into the river Glen at Pinchbeck. This canal was here parallel to the Cardyke at distances of from four to six miles. It could not have been made until the seabank had been thrown up all round Bicker Haven to keep out the tides. The course of these banks show the enormous amount of land near the Wash—about 64,000 acres—that has since been gained by accretion. The Wash, called by Ptolemy “Metaris Æstuarium,” was a bay with an entrance some two miles narrower than at present, into which fell the waters of four tidal rivers—the Ouse, the Nene, the Welland, and the Witham. The Seabank, starting from Wisbech on the Nene estuary, proceeds north for about ten miles, and then curves round west to the Welland estuary below Spalding. But about eight miles farther south is another westerly bank, parallel to the first, from Cowbit to Tydd St. Mary. This bank, called “Ravenbank,” was probably used as a road from Ermine Street into Norfolk, and south of it, between the Welland and the Nene, are three entrenchments, a few miles apart, where Roman remains have been found. About Spalding, where the Westlode—an ancient drain now filled up—fell into the Welland, the Seabank turns north to Surfleet, and then, running west, north, and east to encircle Bicker Haven, reaches the Witham at Redstone Gowt. From this point it can be traced north to Wainfleet, and thence, with intervals, to beyond the entrance to the Humber opposite Spurn Point. Its character varies considerably in different places. Between Boston and Skegness it often appears too broad to be artificial; but in general it is only a few yards wide, at an elevation of from 10 to 20 feet, and is frequently used as a modern road.
Some of these banks were doubtless used also by the Romans as roads, not for wheeled vehicles, but for pack horses in connection with the salt industry. The Romans were well acquainted with the manufacture of salt by evaporating sea water in pans or reservoirs prepared for the purpose. The flat coasts of Lincolnshire are especially favourable to this industry. Remains of such pans can still be detected on Bicker Haven, which is many miles from the present sea-shore; but the principal saltworks appear to have been at Wainfleet St. Mary, just outside the Roman Bank. If Ptolemy’s “Salinæ” is to be placed in Lincolnshire, as some suppose, no spot is so likely as Wainfleet. There was an ancient road into the Fen called the Saltway, or Bridge End Causeway, which crossed the Cardyke between Swaton and Bridge End. It is found on both sides of Bicker Haven, which must have been crossed by a ferry, and thence it points north-east through Frampton and Wyberton to Redstone Gowt and the Seabank beyond the Witham. If this be a Roman way—and remains found along its course in Kesteven seem to prove the fact—it probably belonged to the late Roman period, after the seabanks round the Wash had been completed. But the Wainfleet saltworks may have been developed much earlier, and the salt conveyed by road through Lindsey to Horncastle and Lincoln. Oysters were another commodity that could be procured from the Boston Deeps, though they were not of so fine a quality as those from the Richborough beds, which delighted the epicures of Rome.
One immediate result of the draining and embanking of the Fens would be the more complete occupation of the forest or heath district of Kesteven. That district was intersected by two branches of Ermine Street, which both start from Castor, and may have united at Lincoln. The eastern branch, which enters the county at West Deeping and runs along the high land parallel to the Cardyke for over twenty miles, is the shorter in actual distance; but it was not the main route, and the branch-ways from it across the Fen indicate that it was the later in date. South of Bourn, where was a camp close to the Cardyke, it is known in parts as Langdyke, High Street, and King Street; between Bourn and Sleaford it is generally called Mareham Lane. There was a by-way from it at Morton, which has been traced to the western branch at Great Ponton; and at Threckingham it is crossed from the east by the Saltway just mentioned. On each side of the latter way, about four miles west of Threckingham, tessellated pavements have been found at Haceby and Aisby; and after crossing the western branch at Cold Harbour,[24] near Grantham, the Saltway passes south-west into Leicestershire. At a ford near Sleaford, where coins and much pottery indicate that there was some kind of station, the eastern branch is within six miles of the western at Ancaster; and there was doubtless a cross-road between them, as interments have been found at Rauceby and coins at Bully Wells.
Ancaster, on the western branch of the Ermine Street, is one of those sites which, from a military camp on a main southern route, rose to be a small town, with a population probably engaged in agriculture. It is now generally identified with Causennæ, the station next to Lincoln in the fifth Iter of the Itinerary; but its distance from the colony is only fourteen miles instead of the twenty-six there given. No traces of walls are now visible above-ground, and even Leland, nearly four hundred years ago, spoke doubtfully as to their existence; but since his time their foundations have been met with on the north and west sides. The boundaries of the station, which was nearly square, and was surrounded by a fosse 50 feet wide and 10 feet deep, can still be distinctly seen; and it was defended at the corners by circular towers, the outlines of which on the north-west and south-east are well defined. The area enclosed is about six acres; and the course of Ermine Street, which intersects it, is near the western boundary. This suggests that the town was extended, before the erection of its walls, up the slope towards the east. Its position, on much lower ground than the heights around, was probably chosen partly to provide shelter from the bleak winds of the heath, partly for the sake of two springs which are close to its northern and southern limits. From a description of the place in 1579, it appears that pavements and “arches” had then been discovered within it; but a large part of the area, called the “Castle Close,” has long been under grass. It needs no practised eye to detect that there are foundations beneath the uneven turf, and systematic excavation might yield discoveries of much interest. An immense quantity of coins were found in Stukeley’s time not only within the area but about the surrounding hills. But the most remarkable object—unearthed in the churchyard in 1831—was a small sculptured group of the three Deæ Matres, seated in a sella carved upon a plinth, with a column and a little incense altar on the base in front of them. Statues of these “Protecting Mothers”—who were provincial rather than Roman deities—have been found at the Wall stations of Chester and Birdoswald; there, however, the figures are separate, and not ranged in a single sella. The cemetery of Causennæ seems to have been just outside the southern gate, while north of the village has been found a potter’s kiln and a small milliary with an inscription to Constantine the Great. The latter was not on its original site, and its base had been broken off.[25] On a high hill in Honington, about two miles south-west of Ancaster, is a small British camp, with a triple vallum almost circular, enclosing about an acre and a quarter. This was doubtless occupied by the Romans, for two urns full of coins have been found within it. There was probably a cross-road west of Ancaster, communicating with the Foss Way at East Bridgford (Margidunum) in Nottinghamshire. Coins and pottery have been found at Foston and Allington along the direct line; and the Sewstern grass lane, locally supposed to be Roman, joins it from the south-east.
The eastern branch of Ermine Street can be traced for about four miles north of Sleaford, but its subsequent course is unknown. At or near Sleaford it threw off a branch-way, which passes through Ewerby and North Kyme (where it crosses the Cardyke), and points towards Tattershall and Horncastle. At North Kyme, where two bronze leaf-shaped swords have been found, is a small camp with a double vallum, and two more are on record in Tattershall Park. These entrenchments are in a position to protect the draining operations in the upper fen. Nine miles to the north is Horncastle (in mediæval documents always written Horncastre), which was a castellum, or walled fort, built in the angle (Saxon “Hyrn”) formed by two streams, the Bane and the Waring. The Celtic name of the chief stream is responsible for its identification with the “Banovallum” of the anonymous Ravennas. A few detached portions of the wall can still be seen, showing its area to have been about four and a half acres, with its longer sides (about 200 yards in length) on the north and south. The masonry is rude, but probably only the core remains, the facing-stones having been removed for building purposes in later ages. The only remains known to have been found are coins, pottery, and some leaden coffins outside the walls. This fort may have been built in the first century if coins are any indication of date, for among a large number, covering the whole Roman period, about ten belong to that century. If so, it may have been purely military in origin—built in order to overawe the natives of the Southern Wolds, and so serving the same object as Caistor among those of the north.
But towards the end of the third century, when the Pax Romana had long been established, there arose a new enemy—the Saxon sea-rovers—against whom new measures had to be taken. The first British fleet, which was formed under the leadership of Carausius, had such success against them that its commander seized the supreme power, and for a time maintained the independence of the island. But after the continental Empire resumed its sway in A.D. 296, this fleet was allowed to melt away; and a new land organisation was established, described in the Notitia Imperii, which split up the military command into three divisions, and placed them under the Prætorian Præfect of Gaul. By this arrangement, which may have originated in Constantine’s jealousy of his subordinates, the military force was chiefly massed in the two districts most exposed to invasion—the northern province, under the Duke of the Britains, whose headquarters were at York, and the south-eastern littoral, under the Count of the Saxon Shore. The central and western parts of the island, being much less exposed to danger, were defended only by a few squadrons of cavalry under the Count of the Britains, who had no legion under his command. It has generally been assumed that the northern province was bounded on the south by the Humber.[26] But if the “Saxon Shore” ended, as seems likely, at the eastern side of the Wash, such a division would result in leaving a long stretch of Lincolnshire Marsh, the flat shores of which were peculiarly exposed to invasion, outside the control of both the commanders, who had to defend the east coast. This district would thus be the “Achilles’ heel” of the whole system. Personally I am convinced that the northern province extended to the Wash, and that its southern boundary, which perhaps was ill-defined, was, roughly, the river Nene and Watling Street from High Cross (Venonæ) to Chester. It was essential for security that both banks of the Humber should be under one command; and it is hardly conceivable that Lincoln and York, whose connection by road and water was so intimate, were in different provinces. But though there was apparently no walled fortress on the hilly shore between the Tyne and the Humber, the exposed coast of Lindsey would naturally need some defence of the kind; and direct communication would, of course, be established between the northern province and the forces on the Saxon Shore.
Such communication, I believe, already existed before the Notitia system was set up. The Peddar’s Way, “one of the best preserved Roman roads in East Anglia,”[27] can be traced to-day for 45 miles from the borders of Suffolk (starting no doubt from Colchester) to Holme-on-Sea, at the eastern headland of the Wash. This spot is four miles west of Brancaster, the northernmost fort on the Saxon Shore, and the presumption therefore is that it was laid down before that fort was built. Pointing from the opposite promontory of the Wash (which would have to be crossed by a boat journey of perhaps ten miles) an undoubted Roman road passes by Burgh into the Wolds, and communicates directly through Caistor with the Humber, and by branch-ways with Lincoln and York. The town of Wainfleet (All Saints), some six miles west of this promontory, is often said to have been the Roman haven for the Lindsey coast; but it is singularly poor in Roman remains, and its supposed name of “Vainona” is an invention of the eighteenth century. The road just mentioned is difficult to follow in the Marsh east of Burgh, but there are signs of it outside the Roman Bank west and south of Skegness. Here, according to tradition related by Leland, stood a walled haven town “with a castle,” which was destroyed by the sea not long before his time; and the shifting sandbanks of “The Knock” now covering it must have been the promontory which gave to Skegness its name. Mediæval documents mention the site of this “castle,” but are silent as to its owner; we may therefore infer that it was the ruins of a Roman castellum, which in other instances, both in our county and elsewhere, is called a “castle.” Such a conjecture is incapable of absolute proof; but as Peddar’s Way ends in no walled fort, there would naturally be one on the opposite coast. The coincidence is at least curious that the two Notitia forts of Branodunum (Brancaster) and Præsidium (which has been placed in our county) were both garrisoned by a body of Dalmatian cavalry, whose native shores were marshy tracts indented by deep bays.
Just beyond Burgh—where coins are found, though the station must have been small—the Lindsey road takes to the Wolds, and traverses the high ridge overlooking the Marsh, its straight course for five miles (two only on a modern road) being unmistakable. Coins and pottery have been found in the adjacent parishes of Welton, Willoughby, Well, and Claxby, in the last-named parish chiefly in a well-marked camp overhanging a stream, which here issues from the chalk. At the highest point in the district, where this “way” separates the parishes of Ulceby and Dexthorpe, there was some kind of station or “mansio,” roofed with flanged tiles, in a field where the plough annually turns up many coins and other remains. From South Ormsby the road follows the Blue Stone Heath Road (probably British in origin) along a winding ridge and through a camp, now scarcely traceable, below which, in Worlaby, have been found the walls of a building containing Samian pottery and a quantity of charred corn. Either here or at Ulceby a branch-way may have left this road direct for Horncastle and Tillbridge Lane; its course is not certain, but cinerary urns have been found at Ashby Puerorum, about half-way. At Ludford the main “via” crosses Salters’ Lane from Lincoln, and becomes merged in the “High Street” from Horncastle for nine miles to Caistor, and beyond it for fifteen miles, by Yarborough Camp, to Barton or South Ferriby.[28] Near this road have been found tessellated pavements at Walesby, Claxby, and Bigby. At Barton there are remains of an earthwork called the “Castle Dike,” but much of it has been washed away by the Humber. Another road, long known as Barton “Street,” leaves the first about a mile south of this camp, and passes through or near to Louth; its subsequent course is uncertain, but there are various camps in the Marsh district which may have been connected by it.