B. Military Value of its Position
York is situated on the higher ground, in the angle made by the rivers Ouse and Foss at their junction; a little to the south, the east and the west there are low ridges of mound. The outer, main series of hills which border the central plain, are some dozen miles away, their outer faces being more or less parallel and running very roughly north and south. It seems clear that the site was chosen from the first for its immediate defensive value, the direct result of its geographical features. The position was of both tactical and strategic importance. In Roman times, however, its tactical value decreased when the great wall was built that stretched with its lines of mound, ditch, stone-rampart, and road, and its series of camps and forts, from near the mouth of the Tyne to Solway Firth. Henceforth the wall marked the debatable frontier, but York never lost its strategic value. It was thus used by the Romans, William I., Edward I., Edward II., and Edward III. in their occupation of and their expeditions against the North. It has served as a base depôt and military headquarters for centuries.