At this time, too, began the first appearance of Ireland as a power on the sea. In the fourth century the high-king, Niall of the Hostages, commanding a large fleet of war galleys, invaded Scotland, ravaged the English coasts, and conquered Armorica (Brittany), penetrating as far as the banks of the Loire, where, according to the legend, he was slain by an arrow shot by one of his own men. One of the captives he brought from abroad on one of his early expeditions was a youth named Patrick, afterwards to be the Apostle of Ireland. Niall’s nephew, Dathi, also ard-ri, was a great sea king. He invaded England, crossed to Gaul, and marched as far as the Alps, where he was killed by lightning. He was the last pagan king of Ireland. In perhaps a score of years after the death of Dathi, all Ireland had been converted to Christianity, and its old religion of a thousand years buried so deep that scholars find the greatest difficulty in recovering anything about it. This conservative, obstinate, jealous people overturned its pagan altars in a night, and, ever since, has never put into anything else the devotion, soul and body, of its sacrifices for religion. Christianity profoundly modified Irish life, softened manners, and stimulated learning. Not that the fighting propensities were obliterated. There were indeed many long and peaceful reigns, but the historians record neat little wars, seductive forays and “hostings”, to use the new-old word, to the heart’s content. The Irish character remained fixed in its essentials, but, under the influence of religious enthusiasm, Ireland progressed and prospered in the arts of peace. It would undoubtedly have shared the full progress of western Europe from this time on, but for its insularity. Hitherto its protection, it was now to be its downfall. A hostile power was growing of which it knew nothing.
The Norsemen—the hardy vikings of Norway, Sweden, and Denmark—had become a nation of pirates. Undaunted fighters and able mariners, they built their shapely long ships and galleys of the northern pine and oak, and swept hardily down on the coasts of England, Ireland, France, Spain, and Italy, and the lands of the Levant, surprising, massacring, plundering. In France (Normandy), in England, and lastly in Ireland they planted colonies. Their greatest success was in England, which they conquered, Canute becoming king. Their greatest