With this plan clearly developed he advanced upon the Sunday morning no more than a mile or two to the position in question, fortified it after the fashion which I shall later describe, and camped immediately behind it to see what that Sunday might bring. He could not make off at once, because his horses and his marching men were worn out with the fatigue of the previous day's great march. PART III THE TERRAIN The defensive position taken up by Edward, the Black Prince, upon Sunday the 18th of September 1356, and used by him in the decisive action of the following day, is composed of very simple elements; which are essentially a shallow dip (about thirty feet only in depth), bounded by two slight parallel slopes, the one of which the Anglo-Gascon force held against the advance of the King of France's cosmopolitan troops from the other. We can include all the business of that Monday's battle in a parallelogram lying true to the points of the compass, and measuring three miles and six furlongs from north to south, by exactly two and a half miles from east to west; while the actual fighting is confined to an inner parallelogram no more than two thousand yards from east to west, by three thousand from north to south. The first of these areas is that given upon the coloured map which forms the frontispiece of this little book. The second is marked by a black frame within that coloured map, the main features of which are reproduced in line upon a larger scale on the page opposite this. I have said that the essentials of the Black Prince's defensive plan were: (1) A prepared defensive position, which it might or might not be necessary to hold, coupled with (2) an obstacle, the Miosson River, which (when he should retreat) he could count upon to check pursuit; especially as its little valley was (_a_) fairly deeply cut, (_b_) encumbered by wood, and (_c_) passable for troops only at the bridge of Nouaillé, which he was free to cut when it had served him, and at a somewhat hidden ford which I will later describe. I must here interpose the comment that the bridge of Nouaillé, being of stone, would not have been destroyable during a very active and pressed retreat under the conditions of those times; that is, without the use of high explosives. But it must be remembered that such a narrow passage would in any case check the pursuit, that half an hour's work would suffice to make a breach in the roadway, and perhaps to get rid of the keystones, that a few planks thrown over the gap so formed would be enough to permit archers defending the rear to cross over, that these planks could then be immediately withdrawn, and that the crush of a hurried pursuit, which would certainly be of heavily armed and mounted knights, would be badly stopped by a gap of the kind. I therefore take it for granted that the bridge of Nouaillé was a capital point in Edward's plan.[3] [Illustration]