Hadrian’s Wall is now crowned, except at one point, by the reconstruction in stone by Severus I. ninety years later; hence it was often supposed that the first wall was a stone structure. This idea may now be regarded as thoroughly disproved; the later wall stands upon and hides the foundations of the former, but near Birdoswald Severus’s engineers diverged a little from Hadrian’s line, and the earlier emperor’s construction may still be seen. The turf wall, replaced by stone, ran for seventy-three miles from Gabrosentum (Bowness) to Segedunum (Wallsend). In front of it, where it did not crown precipitous cliffs, was a ditch about 36 feet broad, and perhaps 30 feet deep. At each milestone there was a redoubt (_castellum_), and at more or less regular intervals along the whole line were fifteen large forts. Roughly parallel to the wall ran a military road, and a little way south of it a wide but shallow ditch between mounds, commonly called the ‘Vallum,’ the reason for which is a puzzle. It is best here to adopt Professor Oman’s very reasonable theory that it was the civil boundary of the province. The wall and its forts were constructed by detachments from the legions, but it was garrisoned by the auxiliary cohorts, while the heavy infantry lay in reserve at the old military centres. Twenty-one infantry cohorts and six _alæ_ of cavalry made up the original garrison, and some of them kept their stations for centuries. Nearly three hundred years later there were at least eleven, and probably more, of these regiments still on the wall. Behind, the legions occupied their camps for generation after generation, as if nothing could disturb them. For two hundred and eighty-two years after Hadrian’s visit, Legio VI. lay at York. The XXth ‘Valeria Victrix’ made its home at Deva (Chester) for more than three centuries; while Secunda Augusta, which had landed with Plautius in 43, did not leave Britain until 407, after a sojourn of three hundred and sixty-four years! CHAPTER III THE ROMAN PROVINCE AND THE EARLIER TEUTONIC INVASIONS After Hadrian, in what Florus jokingly termed the great Emperor’s ‘walking about Britain,’ had reorganized the island, and established the famous military frontier, Britain settled down to a more or less eventful existence as a Roman province. The unfortunate results of the enterprise, into which Claudius had perhaps been led partly against his will, soon began to be apparent, even if to all thinking men they were not plain as early as the reign of Hadrian. The military boundary chosen by Trajan’s successor corresponded roughly with the northern border of the Brigantes, but it was not the frontier of Britain, which extended from Clyde to Forth. Therefore, in 140-141, the governor, Lollius Urbicus, the lieutenant of Antoninus Pius, moved the frontier forward to this line, and covered it by another rampart, strengthened by ten forts, only a few miles apart. It was the old, old story--a forward policy can never halt.