Anyhow there is no positive indication that before A.D. 70 the Roman forces had penetrated into the eastern counties beyond the southern shore of the Wash. Some have fancied that the Coritani were subdued by Ostorius (A.D. 50-55), or Paulinus (A.D. 57-62). But the line of advance taken by both generals was to the north-west, along Watling Street, rather than due north; and Ostorius in particular is said to have established a chain of fortified camps—doubtless to secure his communications—from the Nene to the Severn. But when Petilius Cerealis assumed the command in the year A.D. 71, the peace with the Brigantes was broken, and Tacitus represents that the ensuing campaigns, of which he only says that “there were many battles and some not bloodless,” lasted the four years of this command. As his father-in-law, Agricola, was then in command of the Twentieth Legion, Tacitus must have known the facts, and may have reserved a full account of them for his _Histories_, but the portion of the work which deals with this war has not survived. We do not know what were the headquarters of the Roman governors from A.D. 61 to 71, but they were almost certainly south of the Wash. An advance, therefore, against the Brigantes of Yorkshire must have brought them along the western branch of Ermine Street to Lincoln, as any good map will show. To the west they had the difficult country of the Peak, to the east the dreaded Fenland, and there is no direct road through Nottinghamshire to York. Starting from Durobrivæ (Castor)—which was perhaps the most easterly fort on the Nene, and as such occupied by the Ninth Legion in A.D. 61—and taking the line of road afterwards laid down, the army would at first bend to the north-west to avoid the immediate neighbourhood of the fens. Along this road, still traceable, and called in parts the “High Dyke,” there are camps at Casterton, Easton, and Ancaster, the last of which subsequently became an important station. At length, after traversing the high ground of the Cliff, the army would appear on the ridge of Canwick, facing the “Lincoln Gap.” On the crest of the opposite hill, from which they were separated by a flooded valley then reached by the tide, lay a strong British “oppidum.” It would be no light matter to take such a position by storm, but taken it was, whether by force or through a timely surrender. When once occupied, this stronghold would be turned into a military earthwork and used as a base of operations against the Brigantes, thus becoming the nucleus of the subsequent city. The advance into Yorkshire, if supported by a fleet, may have been made from the north gate of the camp by the direct line of Ermine Street to Winteringham on the Humber, for the Ouse was then navigable as far as York. But it seems more likely that this was a land expedition, and that the earliest road was that which leaves the main Ermine Street four miles north of Lincoln, and under its present name