The rectangular parallelogram so formed is nearly equally divided between land and sea, the south-eastern half being a portion of Northern France, and the north-western half the English Channel. The land half is thus roughly triangular, having Paris at its extreme south-eastern corner, Calais at its extreme north-eastern, the neighbourhood of Avranches with St Malo Bay at its south-western corner. It includes part of the provinces of Normandy, the Ile de France, Picardy and Artois, and part, or all, of the modern departments of the Manche, Orne, Calvados, Eure, Seine-et-Oise, Seine, Seine-Inférieure, Oise, Somme, and Pas-de-Calais. It will be seen that this territory is nearly evenly divided by the River Seine, and the campaign of Crécy is also divided by that river in the sense that the English advance took place wholly to the west of it, and the English retreat wholly to the east of it. The campaign, as a whole, resolves itself (up to and including the Battle of Crécy, which is the subject of this book, and excluding the continuation of the march after Crécy, and the capture of Calais) into an advance from the Channel coast to Paris, and a retreat from Paris to the Channel again, the two portions being divided by the crossing of the Seine at Poissy. The advance leaves the coast at the summit of that projection of Normandy called the Cotentin, and proceeds a little south of east towards Paris, the walls of which are reached by its outermost skirmishers, while the main army crosses the Seine at Poissy. The retreat is effected from Poissy northward to the victorious field of Crécy, and later from Crécy, on the same line, to the siege and capture of Calais. The time occupied from the day of landing to the day of the Battle of Crécy inclusive, is but forty-six days, of which not quite two-thirds are taken up by advance, and rather more than a third by the retreat. The English troops landed on Wednesday, July 12th, 1346. They crossed the Seine at Poissy upon August 14th. They fought at Crécy upon Saturday, August 26th. The total distance traversed by the main body in these two limbs of the campaign is instructive as showing the leisure of the first part, its advance, and the precipitancy of the second part, its retreat. The distance by road as the army marched from St Vaast, where it landed, across the river at Poissy, and so to Crécy, was a total of 345 miles. Of this the first part, or advance, was 215, the second part, or retreat, 130. The first part occupied, counting the day of landing and the day of crossing at Poissy, not less than 34 days, while the latter portion or retreat of 130 miles, including the day of battle itself, took up not more than 12 days, or, excluding the battle, only 11. The average rate of the advance was not more than 6-1/4 miles a day, the average rate of the retreat very nearly double.