Caistor, which stands on a tongue or spur half a mile west of “High Street,” is a very interesting spot. Its position is one of great strength, and suggests a British origin, as it has all the characteristics of a “promontory fortress.” It was surrounded by a wall, strengthened at intervals by turrets or bastions, one of which remains in ruins on the south side of the churchyard; there is also a considerable fragment of the western wall in the garden of Grove Cottage. The exact area of the station is difficult to estimate, as the north and east walls have disappeared; but it was perhaps ten or twelve acres. There are two fine springs issuing from the rock on the south side of the fortress. In the churchyard, which is entirely within the area, Roman coins and pottery are constantly found, but stone foundations seem absent, and the fine ornamental ware is scarce. In early records the site is often termed Than—or Thwang—Castre, probably from the tongue of land on which it stands, and from this name Geoffrey of Monmouth ascribes its building[29] to Hengist, according to the legend by which that mythical chieftain encompassed an area granted him with “thongs” of ox-hide. The same story is told of other “Tong Castles” in Shropshire and Kent, and seems borrowed from Virgil’s account of the foundation of Carthage. The occupation of our county by the Romans appears to have been more thorough than is sometimes supposed. Only in the north-west corner—the Isle of Axholme—which was then marshy and exposed to the Trent floods, are traces of their presence wanting. Much more doubtless remains to be discovered, for Eastern Lindsey is still comparatively unexplored. The district seems to have been, as now, largely agricultural; and the finding of over twenty villa sites in Kesteven and Lindsey indicates that the wealthier class of landowners resided on their estates. This circumstance points to a long period of peace, which may have lasted more than a century—from about A.D. 170. During that time the road system would be completed, and the industries of potters and saltworkers, so characteristic of our county, gradually developed. But a time came when the Pictish and Saxon marauders must have made great havoc in a district which had a long sea-front, and was but slightly protected by walled towns. In the year 368 these two sources of trouble united to overwhelm the province like an invading flood. The northern tribes broke across the Wall of Hadrian, and in concert with the sea-rovers, who had defeated and slain the Count of the Saxon Shore, advanced their plundering hosts to the very gates of London. By a series of victories, Theodosius, the ablest of the imperial generals, gave the province a short breathing-space. But the weight of taxation imposed by an over-centralised government was gradually crushing the provincials; and discontent gave an opening for the revolt of various usurpers in the last days of the Roman rule.