Raids so extensive could hardly have been effected without help from within, and the dim history of the time allows us to see not merely an increase of disunion between the Romanized and un-Romanized population of Britain, but even an alliance between the last and their free kinsfolk, the Picts. The struggles of Britain, however, lingered on till dangers nearer home forced the Empire to recall its legions and leave the province to itself. Ever since the birth of Christ the countries which lay round the Mediterranean Sea, and which then comprehended the whole of the civilized world, had rested in peace beneath the rule of Rome. During four hundred years its frontier had held at bay the barbarian world without - the Parthian of the Euphrates, the Numidian of the African desert, the German of the Danube or the Rhine. It was this mass of savage barbarism that at last broke in on the Empire as it sank into decay. In the western dominions of Rome the triumph of the invaders 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 border-land between Italy and the Rhone. The East-Goths ruled at last in Italy itself.
And now that the fated hour was come, the Saxon and the Engle too closed upon their prey.
It was to defend Italy against the Goths that Rome in 410 recalled her legions from Britain. The province, thus left unaided, seems to have fought bravely against its assailants, and once at least to have driven back the Picts to their mountains in a rising of despair. But the threat of fresh inroads found Britain torn with civil quarrels which made a united resistance impossible, while its Pictish enemies strengthened themselves by a league with marauders from Ireland, (Scots as they were then called), whose pirate-boats were harrying the western coast of the island, and with a yet more formidable race of pirates who had long been pillaging along the British Channel. These were the English. We do not know whether it was the pressure of other tribes or the example of their German brethren who were now moving in a general attack on the Empire from their forest homes, or simply the barrenness of their coast, which drove the hunters, farmers, fishermen, of the English tribes to sea. But the daring spirit of their race already broke out in the secresy and suddenness of their swoop, in the fierceness of their onset, in;he careless glee with which they seized either sword or oar. "Foes are they," sang a Roman poet of the time, "fierce beyond other foes, and cunning as they are fierce; the sea is their school of war, and the storm their friend; they are sea-wolves that live on the pillage of the world." To meet the league of Pict, Scot, and Saxon by the forces of the province itself became impossible; and the one course left was to imitate the fatal policy by which the Empire had invited its own doom while striving to avert it, the policy of matching barbarian against barbarian.
The rulers of Britain resolved to break the league by detaching from it the freebooters who were harrying her eastern coast, and to use their new allies against the Pict. By the usual promises of land and pay, a band of warriors from Jutland were drawn for this purpose in 449 to the shores of Britain, with their chiefs, Hengest and Horsa, at their head.