Experience however had taught the Mercians the worthlessness of raids like these and Offa resolved to create a military border by planting a settlement of Englishmen between the Severn, which had till then served as the western boundary of the English race, and the huge “Offa’s Dyke” which he drew from the mouth of Wye to that of Dee.  Here, as in the later conquests of the West-Saxons, the old plan of extermination was definitely abandoned and the Welsh who chose to remain dwelled undisturbed among their English conquerors.  From these conquests over the Britons Offa turned to build up again the realm which had been shattered at Burford.  But his progress was slow.  A reconquest of Kent in 775 woke anew the jealousy of the West-Saxons; and though Offa defeated their army at Bensington in 779 the victory was followed by several years of inaction.  It was not till Wessex was again weakened by fresh anarchy that he was able in 794 to seize East-Anglia and restore his realm to its old bounds under Wulfhere.  Further he could not go.  A Kentish revolt occupied him till his death in 796, and his successor Cenwulf did little but preserve the realm he bequeathed him.  At the close of the eighth century the drift of the English peoples towards a national unity was in fact utterly arrested.  The work of Northumbria had been foiled by the resistance of Mercia; the effort of Mercia had broken down before the resistance of Wessex.  A threefold division seemed to have stamped itself upon the land; and so complete was the balance of power between the three realms which parted it that no subjection of one to the other seemed likely to fuse the English tribes into an English people.

Chapter III
wessex and the northmen
796-947

[Sidenote:  The Northmen]

The union which each English kingdom in turn had failed to bring about was brought about by the pressure of the Northmen.  The dwellers in the isles of the Baltic or on either side of the Scandinavian peninsula had lain hidden till now from Western Christendom, waging their battle for existence with a stern climate, a barren soil, and stormy seas.  It was this hard fight for life that left its stamp on the temper of Dane, Swede, or Norwegian alike, that gave them their defiant energy, their ruthless daring, their passion for freedom and hatred of settled rule.  Forays and plunder raids over sea eked out their scanty livelihood, and at the close of the eighth century these raids found a wider sphere than the waters of the northern seas.  Tidings of the wealth garnered in the abbeys and towns of the new Christendom which had risen from the wreck of Rome drew the pirates slowly southwards to the coasts of Northern Gaul; and just before Offa’s death their boats touched the shores of Britain.  To men of that day it must have seemed as though the world had gone back three hundred years.  The same northern fiords poured forth their pirate-fleets