It is clear that, as time went on and the power of Rome in Britain grew weaker, the defensive character of the great wall and that of the stations which it connected were emphasised at the expense of their character as bases of active warfare. But it must be repeated that Roman stations in Britain were not planned to form impregnable shelters for communities mainly pastoral. They were centres for bodies of fighting men, linked to each other by a splendid system of roads. The Roman station at Dorchester, the lines of which are so well preserved to-day, was founded, not within the ramparts of Maiden Castle or Poundbury, but on the lower slopes near the passage of the Frome. The single rampart and single ditch of a Roman town were almost invariable. Free egress as well as entrance, provisions for attack as well as defence, were necessary; and, with these objects in view, immense earthen defences, such as those of Maiden Castle, would be cumbersome. Bodies of Roman troops, as at Lincoln or Colchester, occasionally occupied part of the _enceinte_ of a British settlement; but it is very rarely that, as in the case of Old Sarum, we find a British hill fort which also probably served as a Roman station. In this instance, the occupation of the fort was due, doubtless, to its neighbourhood to the military road: the road would not have been brought out of its way to include the fort in its course. Roman stations, although they differed in size, were small and compact, when contrasted with the large and straggling areas occupied by the British settlers. Suburbs naturally grew up outside their walls, and sometimes, although not very often, the walled enclosure was extended to include a growing outer district. This is supposed by many antiquaries to have happened at Lincoln, where the original Roman station occupied the summit of the hill north of the great bend of the Witham, which here turns from its northerly course due eastward. After the city of Lincoln had settled down to civil life, practically the whole slope of the hill south of the first _enceinte_ was included within the city and encircled by a wall. Part of the east wall of this later enclosure is still visible: the Stonebow, the medieval south gate of the city, about a hundred yards from the river and the bridge, appears to be on the site of the later south gateway of Roman Lincoln.[22] CHAPTER II THE SAXON AND DANISH PERIOD