D. 2.--Thus our earliest notice of Britain in this period tells us that Hadrian (A.D. 120), our first Imperial visitor since Claudius (A.D. 44), found it needful (after a revolt which cost many lives, and involved, as it seems, the final destruction of the unlucky Ninth Legion, which had already fared so badly in Boadicea's rebellion[256]) to supplement Agricola's rampart, between Forth and Clyde, with another from sea to sea, between Tynemouth and Solway, "dividing the Romans from the barbarians."[257] This does not mean that the district thus isolated was definitely abandoned,[258] but that its inhabitants were so imperfectly Romanized that the temptation to raid the more civilized lands to the south had better be obviated. The Wall of Hadrian marked the real limit of Roman Britain: beyond it was a "march," sometimes strongly, more often feebly, garrisoned, but never effectually occupied, much less civilized. The inhabitants, indeed, seem to have rapidly lost what civilization they had. Dion Cassius describes them, in the next generation, as far below the Caledonians who opposed Agricola, a mere horde of squalid and ferocious cannibals,[259] going into battle stark-naked (like their descendants the Galwegians a thousand years later),[260] having neither chief nor law, fields nor houses. The name Attacotti, by which they came finally to be known, probably means _Tributary_, and describes their nominal status towards Rome. D. 3.--How hopeless the task of effectually incorporating these barbarians within the Empire appeared to Hadrian is shown by the extraordinary massiveness of the Wall which he built[261] to keep them out from the civilized Provinces[262] to the southwards. "Uniting the estuaries of Tyne and Solway it chose the strongest line of defence available. Availing itself of a series of bold heights, which slope steadily to the south, but are craggy precipices to the north, as if designed by Nature for this very purpose, it pursued its mighty course across the isthmus with a pertinacious, undeviating determination which makes its remains unique in Europe, and one of the most inspiriting scenes in Britain."[263] Its outer fosse (where the nature of the ground permits) is from 30 to 40 feet wide and some 20 deep, so sloped that the whole was exposed to direct fire from the Wall, from which it is separated by a small glacis [_linea_] 10 or 12 feet across. Beyond it the upcast earth is so disposed as to form the glacis proper, for about 50 feet before dipping to the general ground level. The Wall itself is usually 8 feet thick, the outer and inner faces formed of large blocks of freestone, with an interior core of carefully-filled-in rubble. The whole thus formed a defence of the most formidable character, testifying strongly to the respect in which the valour of the Borderers against whom it was constructed was held by Hadrian and his soldiers.[264]