Caledonia alone, defended by its barren mountains, and by the contempt which the Romans entertained for it, sometimes infested the more cultivated parts of the island by the incursions of its inhabitants.

The better to secure the frontiers of the empire, Adrian, who visited this island, built a rampart between the River Tyne and the Frith of Solway; Lollius Urbicus, under Antoninus Pius, erected one in the place where Agricola had formerly established his garrisons, Severus, who made an expedition into Britain, and carried his arms to the most northern extremity of it, added new fortifications to the wall of Adrian; and during the reigns of all the Roman emperors, such a profound tranquillity prevailed in Britain, that little mention is made of the affairs of that island by any historian.

The only incidents which occur, are some seditions or rebellions of the Roman legions quartered there, and some usurpations of the imperial dignity by the Roman governors.

The natives, disarmed, dispirited, and submissive, had lost all desire and even idea of their former liberty and independence.
But the period was now come, when that enormous fabric of the Roman empire, which had diffused slavery and oppression, together with peace and civility, over so considerable a part of the globe, was approaching towards its final dissolution.

Italy, and the centre of the empire, removed during so many ages from all concern in the wars, had entirely lost the military spirit, and were peopled by an enervated race, equally disposed to submit to a foreign yoke, or to the tyranny of their own rulers.