In Durham, the church of Chester-le-Street, which contains some traces of pre-Conquest work, was originally inside a Roman camp, now unfortunately destroyed[42]. Ebchester Church, also in Durham, stands at the south-western corner of the ancient Vindomora, and has a foundation of large squared stones, but little can now be seen of the surrounding fortifications[43]. While surveying the North of England, we notice Moresby, near Whitehaven[44]. In Scotland, to mention but one case, we have the Cistercian Abbey of Cupar-Angus, which was built, in A.D. 1164, within the boundaries of a Roman camp[45]. Returning to the south, we discover, in the churchyard of St John’s-sub-Castro, at Lewes, a small Roman camp, of which the vallum is still traceable[46]. Porchester, in Hampshire, is a square-walled fort which occupies an area of 9 acres, and which encloses a Mediaeval keep and bailey-court at the north-west corner, and a Mediaeval church and graveyard at the south-west corner[47]. In like manner, the Norman church at Silchester nestles within the celebrated Roman settlement. Here our list of Christian churches placed within Roman camps must be curtailed, for we have still to consider earthworks belonging to an earlier period. The reason for separating the two classes of earthworks is, that those churches which were reared within Roman camps may, probably, in some cases, have replaced more primitive buildings, while those built inside prehistoric forts most likely had no predecessors. In other words, we shall have to search for different motives inducing the choice of the two respective series of sites. At the very threshold of the inquiry a marked difference is noticed: the pre-Roman earthworks contained no building material to entice the churchmen within their boundaries. Turning to individual examples, we find a most instructive case at Knowlton or Knollton, Dorsetshire, four miles south-west of Cranborne. Here, a ruined church built by Norman labour, though not necessarily representing the first church reared on the spot, stands within a round British earthwork (Fig. 4). The ditch, or fosse, of the enclosure is situated on the inner side, as in the renowned earthwork at Avebury, Wiltshire. The Saxon church at Avebury dates in the main, perhaps, from the early tenth century, and stands just outside the vallum. Some writers have inferred, from the presence of the inner fosse, that these enclosures had religious, or, at least, sepulchral associations. The Knowlton earthwork is one of a group, and close by is a cluster of ancient, storm-beaten yews[48]. Such a collocation, as will be seen in Chapter IX., is not without significance. [Illustration: FIG. 4. Ruins of Knowlton Church, Dorset, standing within an ancient earthwork.]