The distressful island of Ireland was at this moment enjoying the anarchy which had reigned therein since the dawn of history. Its state had grown even more unhappy than before since the Danish invasions of the 10th century, which had not welded the native kingdoms into unity by pressure from without--as had been the case in England--but had simply complicated affairs, by setting up two or three alien principalities on the coastline. As in England, the vikings had destroyed much of the old civilization; but they had neither succeeded in occupying the whole country nor had they been absorbed by the natives. The state of the island was much like that of England in the days of the Heptarchy: occasionally a "High King" succeeded in forcing his rivals into a precarious submission; more usually there was not even a pretence of a central authority in the island, and the annals of objectless tribal wars formed its sole history. King Henry's eyes had been fixed on the faction-ridden land since the first years of his reign. As early as 1155 he had asked and obtained the approval of Pope Adrian IV., the only Englishman who ever sat upon the papal throne, for a scheme for the conquest of Ireland. The Holy See had always regarded with distaste the existence in the West of a nation who repudiated the Roman obedience, and lived in schismatical independence, under local ecclesiastical customs which dated back to the 5th century, and had never been brought into line with those of the rest of Christendom. Hence it was natural to sanction an invasion which might bring the Irish within the fold. But Henry made no endeavour for many years to utilize the papal grant of Ireland, which seems to have been made under the preposterous "Donation of Constantine," the forged document which gave the bishop of Rome authority over all islands. It was conveniently forgotten that Ireland had never been in the Roman empire, and so had not even been Constantine's to give away.