The Teutonic peoples, triumphant conquerors of the land, had carried their victories over the Roman Empire to the edge of the seas that guarded Ireland. But fresh hordes of warriors were gathering in the north, conquerors of the ocean. The Scandinavians had sailed out on "the gulf's enormous abyss, where before their eyes the vanishing bounds of the earth were hidden in gloom." An old English riddle likened the shattering iceberg swinging down from Arctic waters to the terror of the pirate's war-ship--the leader on the prow as it plunged through the sea, calling to the land, shouting as he goes, with laughter terrible to the earth, swinging his sharp-edged sword, grim in hate, eager for slaughter, bitter in the battle-work. They came, "great scourers of the seas--a nation desperate in attempting the conquest of other realms." The Scandinavian campaigns of the ocean affected Ireland as no continental wars for the creation or the destruction of the Roman Empire had done. During two hundred years their national life, their learning, their civilisation, were threatened by strangers. The social order they had built up was confronted with two new tests--violence from without, and an alien population within the island. We may ask how Irish civilisation met the trial. The Danes fell on all the shores of England from the Forth to the Channel, the land of the Picts northward, Iona and the country of the Scots to the west, and Bretland of the Britons from the Clyde to the Land's End: in Ireland they sailed up every creek, and shouldering their boats marched from river to river and lake to lake into every tribeland, covering the country with their forts, plundering the rich men's raths of their cups and vessels and ornaments of gold, sacking the schools and monasteries and churches, and entering every great king's grave for buried treasure. Their heavy iron swords, their armour, their discipline of war, gave them an overwhelming advantage against the Irish with, as they said, bodies and necks and gentle heads defended only by fine linen. Monks and scholars gathered up their manuscripts and holy ornaments, and fled away for refuge to Europe.