To the last indeed the distance of the island from the seat of empire left her less Romanized than any other province of the west.  The bulk of the population scattered over the country seem in spite of imperial edicts to have clung to their old law as to their old language, and to have retained some traditional allegiance to their native chiefs.  But Roman civilisation rested mainly on city life, and in Britain as elsewhere the city was thoroughly Roman.  In towns such as Lincoln or York, governed by their own municipal officers, guarded by massive walls, and linked together by a network of magnificent roads which reached from one end of the island to the other, manners, language, political life, all were of Rome.

For three hundred years the Roman sword secured order and peace without Britain and within, and with peace and order came a wide and rapid prosperity.  Commerce sprang up in ports among which London held the first rank; agriculture flourished till Britain became one of the corn-exporting countries of the world; the mineral resources of the province were explored in the tin mines of Cornwall, the lead mines of Somerset or Northumberland, and the iron mines of the Forest of Dean.  But evils which sapped the strength of the whole empire told at last, on the province of Britain.

Wealth and population alike declined under a crushing system of taxation, under restrictions which fettered industry, under a despotism which crushed out all local independence.  And with decay within came danger from without.  For centuries past the Roman frontier had held back the Barbaric world beyond it—­the Parthian of the Euphrates, the Numidian of the African desert, the German of the Danube or the Rhine.  In Britain a wall drawn from Newcastle to Carlisle bridled the British tribes, the Picts as they were called, who had been sheltered from Roman conquest by the fastnesses of the Highlands.

It was this mass of savage barbarism which broke upon the empire as it sank into decay.  In its western dominions the triumph of these assailants was complete.  The Franks conquered and colonized Gaul.  The West Goths conquered and colonized Spain.  The Vandals founded a kingdom in Africa.  The Burgundians encamped in the borderland between Italy and the Rhone.  The East Goths ruled at last in Italy itself.

It was to defend Italy against the Goths that Rome in the opening of the fifth century withdrew her legions from Britain, and from that moment the province was left to struggle unaided against the Picts.  Nor were these its only enemies.  While marauders from Ireland, whose inhabitants then bore the name of Scots, harried the west, the boats of Saxon pirates, as we have seen, were swarming off its eastern and southern coasts.

For forty years Britain held bravely out against these assailants; but civil strife broke its powers of resistance, and its rulers fell back at last on the fatal policy by which the empire invited its doom while striving to avert it, the policy of matching barbarian against barbarian.  By the usual promises of land and pay a band of warriors was drawn for this purpose from Jutland in 449 with two ealdormen, Hengist and Horsa, at their head.