"He looked and saw wide territory spread Before him; towns and rural works between, Cities of men, with lofty gates and towers, Concourse in arms, fierce forces threatening war-- Assaulting: others, from the wall defend With dart and javelin, stones and sulphurous fire: On each hand slaughter and gigantic deeds." MILTON'S PARADISE LOST, BOOK XI. The fortified line erected by Agricola was soon broken through by the northern tribes, and the Emperor Adrian erected a much stronger barrier, though considerably within the former; and this extended from the Tyne to the Solway, crossing the whole breadth of that portion of the island. Urbicus, as if determined that the Romans should not lose an inch of territory which they had once possessed, restored the more northern boundary which Adrian had abandoned, and once more stretched the Roman frontier between the Friths of Clyde and Forth; they thus possessed two walls, the more northern one, first begun by Agricola, and the southern one, erected by Adrian. Forts were built at little more than a mile distant from each other along this line, and a broad rampart ran within the wall, by which troops could readily march from one part to another. This outer barrier was the scene where many a hard contest took place, and in the reign of Commodus it was again broken down, and the country ravaged up to the very foundations of the wall of Adrian. This skirmishing and besieging, building up and breaking down of barriers, lasted for nearly a century, during which period scarcely a single event transpired in Britain of sufficient importance to be recorded, though there is every proof that the Britons were, in the meantime, making rapid strides in civilization; for England rested securely under the guardianship of the Roman arms. The battles fought at the northern barriers disturbed not the tranquillity of the southern parts of the island. It was not until the commencement of the third century, when old and gouty, and compelled to be borne at the head of his army in a litter, that the Emperor Severus determined to conquer the Caledonians, and boldly sallied out for that purpose beyond the northern frontier. His loss was enormous, and between war with the natives, and the wearisome labour in making roads, felling forests, and draining marshes, which had hitherto been impassable to the Roman troops, fifty thousand soldiers were sacrificed. Nothing daunted, however, the gouty old emperor still pressed onward, until he reached the Frith of Moray, and was struck with the difference in the length of the days, and shortness of the nights, compared with those in southern latitudes. Saving making a few new roads, and receiving the submission of the few tribes who chanced to lie in his way, he appears to have done nothing towards conquering this hardy race; so he returned to Newcastle, and began to build a stronger barrier than any of his predecessors had hitherto erected. On the northern side of this