The line along which the Black Prince threw up entrenchments was the head of the slight slope upon the Nouaillé or eastern side of the depression I have mentioned. It ran from the farm Maupertuis (now called La Cardinerie) to the site of those out-buildings which surround the modern steadings of Les Bordes, and to-day bear the name of La Dolerie. The length of that line was, almost to a foot, one thousand English yards, and it will easily be perceived that even with his small force only a portion of his men were necessary to hold it. Its strength and weakness I shall discuss in a moment. This line faces not quite due west, indeed nearly twenty degrees north of west.[4] Its distance as the crow flies from the Watergate of Poitiers is just under seven kilometres, or, as nearly as possible, four miles and six hundred and fifty English yards.[5] While its bearings from the town of Poitiers, or the central part thereof, is a trifle south of due south-east.[6]
The line thus taken up, and the depression in front of it, are both singularly straight, and the slope before the entrenchments, like its counterpart opposite, is regular, increasing in depth as the depression proceeds down towards the Miosson, which, at this point, makes a bend upward to meet, as it were, the little valley. A trifle to the south of the centre of the line there is a break in the uniformity of the ridge, which comes in the shape of a little dip now occupied by some tile-works; and on the further, or French, side a corresponding and rather larger cleft faces it; so that the whole depression has the shape of a long cross with short arms rather nearer its base than its summit. Just at the end of the depression, before the ground sinks abruptly down to the river, the soil is marshy.
Leading towards this position from Poitiers there was and is but one road, a winding country lane, now in good repair, but until modern times of a poor surface, and never forming one of the great high roads. The importance of this unique road will be seen in a moment.
There had once existed, five hundred yards from the right of the Black Prince's entrenched line, a Roman road, the traces of which can still be discovered at various parts of its course, but which, even by the time of Poitiers, had disappeared as a passable way. The only approach remaining, as I have said, was that irregular lane which formed the connection between Poitiers and Nouaillé.