3. Of the Duke of the Britains we have only here to remark that he appears to have had under his disposition the Sixth legion, stationed at York, and numerous detachments of auxiliary troops in Yorkshire, Westmorland and Lancashire, and _item per lineam valli_ (also along the line of the wall) the various auxiliary cohorts raised in Spain, Gaul and Germany, to whom reference has already been made, and who are to all students of the literature of the Roman wall among the most interesting elements of the army of the empire. Meanwhile events were rapidly ripening towards the catastrophe which was to make the solemn _Notitia Imperii_ a mere hunting-ground for the archæologist. In 395 died the great Emperor Theodosius, who had for a generation staved off the ruin which seemed inevitable at the death of Valens. He was succeeded by his two sons, Arcadius and Honorius, who, with about equal incapacity, presided over the collapse of the eastern and the western half of the empire. For the first thirteen years, however, of the reign of Honorius his incapacity was somewhat veiled by the courage and ability of the Vandal soldier Stilicho, whom Theodosius had left as the guardian of his son. When in the year 400 Alaric, the far-famed King of the Goths, entered Italy, Stilicho undertook the long and wearisome campaigns, partly, as it would seem, north of the Alps, but chiefly in what we now call Piedmont and Lombardy, by which Alaric’s designs on Rome were foiled, and at last in the year 403 the Goths were driven forth from Italy. But in order to avert the danger which thus threatened the heart of the empire, it was necessary seriously to weaken the defence of its extremities. One of the three Roman legions quartered in Britain (probably the Twentieth) was recalled to Italy and apparently never returned. Three years after the repulse of Alaric came in 406 the great cataclysm of the irruption of barbarian hordes, Vandals, Sueves, Burgundians and Alans into Gaul, which led, though not immediately, to the severance of Gaul and Spain from the empire. The inrush of the barbarians spread terror even into Britain, and caused the soldiers, weary of the inept government which was manifestly ruining the empire, to elect an emperor on their own account, and set up, as it were, a “government of national defence”. But revolutionary rulers of this kind are more easily proclaimed than established. First a certain Marcus was proclaimed: then as they found that “he did not suit their tempers” he was slain, and a British citizen named Gratian was invested with the purple, crowned with the diadem and surrounded with a bodyguard. After four months Gratian also was deposed and murdered, and thereupon a private soldier of the meanest rank, named Constantine, who had nothing but that great historic name to recommend him, was robed in the imperial purple. He at once crossed over into Gaul, where he maintained himself with varying