the result was that the northern tribes beyond the Tay retained their independence. From the recall of Agricola till the accession of the Emperor Hadrian, A.D. 117, nothing is known of the condition of this part of the island. Hadrian visited Britain in the year 120, and appears to have put down a threatened insurrection by giving up Agricola's line of forts, and limiting the frontier of the province to a line right across the territory of the Brigantes from the Solway Firth to the river Tyne. Along this line he constructed an immense barrier consisting of, first, on the north side, a ditch, then a stone wall, and then an earthen rampart. Between the two latter were roads for the transmission of troops, with stations, castles, and watch-towers. But this barrier did not act for a long time as a check to the independent section of the Brigantes, who, early in the reign of Antoninus, crossed the wall and overran portions of the Roman Province. But Lollius Urbicus, who was sent to Britain, quickly subdued these hostile tribes (A.D. 139), and again extended the Province to its former limit, viz., the line between the Firths of Forth and Clyde, where he constructed an earthen rampart--"Alio muro cespiticio submotis barbaris ducto." In A.D. 162 an attempt on the Province by the northern tribes was quelled by Calphurnius Agricola. Twenty years later they made another formidable irruption into the Province, but were repelled by Marcellus Ulpius. In A.D. 208 the Emperor Severus found it necessary to come in person to repel these frequent and formidable attacks of the northern barbarians, whom we now find under the names of Mæatæ and Caledonii. The former occupied the lower lands next the wall, and the latter the mountainous regions beyond, but notwithstanding the difference in name, they appear to have been virtually the same people.