A. 7.—­His men were no expert mariners like their adversaries; and, for this very reason, were ready, with their Caesar at their head, to put to sea in threatening weather, which made their better-skilled pilots hesitate.  “What can we fear?” was the cry, “Caesar is with us.”  Dropping down the Seine with the tide on a wild and rainy morning, they set sail with a cross wind, probably from the north-east, a rare thing with ancient ships.  As they neared the British coast the breeze sank to a dead calm, with a heavy mist lying on the waveless sea, in which the fleet found it impossible to keep together.  One division, with Constantius himself on board, made their land-fall somewhere in the west, perhaps at Exeter, the other far to the east, possibly at Richborough.

A. 8.—­But the wonderful luck which attended Constantius, and on which his panegyrists specially dwell, made all turn out for the best.  The mist enabled both his divisions to escape the notice of the British fleet, which was lying off the Isle of Wight on the watch for him; and the unexpected landing at two such distant points utterly demoralized the usurper.  Of the large force which had been mustered for land defence, only the Frankish auxiliaries could be got together in time to meet Constantius—­who, having burnt his ships (for his only hope now lay in victory), was marching, with his wonted speed, straight on London.  One battle,[328] in which scarcely a single Roman fell on the British side, was enough; the corpse of Allectus [ipse vexillarius latrocinii] was found, stripped of the Imperial insignia, amongst the heaps of slain barbarians, and the routed Franks fled to London.  Here, while they were engaged in sacking the city before evacuating it, they were set upon by the eastern division of the Roman army (under Asclepiodotus the Praetorian Prefect)[329] and slaughtered almost to a man.  The rescued metropolis eagerly welcomed its deliverers, and the example was followed by the rest of Britain; the more readily that the few surviving Franks were distributed throughout the land to perish in the provincial amphitheatres.

A. 9.—­The Diocletian system was now introduced; and, instead of Hadrian’s old divisions of Upper and Lower Britain, the island south of his Wall was distributed into four Provinces, “Britannia Prima,” “Britannia Secunda,” “Maxima Caesariensis,” and “Flavia Caesariensis.”  That the Thames, the Severn, and the Humber formed the frontier lines between these new divisions is probable.  But their identification, in the current maps of Roman Britain, with the later Wessex, Wales, Northumbria, and Mercia (with East Anglia), respectively, is purely conjectural.[330] All that we know is that when the district between Hadrian’s Wall and Agricola’s Rampart was reconquered in 369, it was made a fifth British Province under the name Valentia.  The Governor of each Province exercised his functions under the “Vicar” of the “Diocese,” an official of “Respectable” rank—­the second in precedence of the Diocletian hierarchy (exclusive of the Imperial Family).