Now, Henry did not wish to see one of his vassals building up a great kingdom in Ireland, independent of his authority. So, taking advantage of the papal authorization that he had so long kept by him, he crossed himself in 1171 with a great army and fleet, landed at Waterford, and marched to Dublin. He had no trouble in getting his authority recognized. Not only did Strongbow do him homage for the kingdom of Leinster, but, one after another, most of the native Irish kings came to his court and paid allegiance to him. From henceforth the Kings of England might call themselves "Lords of Ireland," but their power in the island was not very easy to exercise, nor did it extend to the remoter corners of the land. About half the soil of Ireland was seized by English and Norman adventurers, who built themselves castles and held down the Celts around them. The other half, mostly consisting of the more rugged and barren districts, remained in the hands of the native chiefs. But the settlers in the course of time intermarried with the Irish, and adopted many of their customs, so that they became tribal chiefs themselves. A century later the grudge between the settlers and the natives was still bitter, but they had become so closely assimilated that it was hard for a stranger to distinguish them. The one were as turbulent, clannish, fierce, and barbarous as the other. Only on the east coast round Dublin, in the district that was afterwards known as the English 'Pale,' did the Anglo-Irish dwell in a settled and civilized manner of life, and obey the King of England's mandates. The larger part of the island had to be reconquered four centuries after. Perhaps the only permanent and immediate result of Henry's visit to Ireland was the submission of the Irish Church to the Pope. In a synod held at Cashel in 1172, all the bishops of the land acknowledged the papal supremacy, and abandoned the old customs of their Church. Thus the papal yoke was the first and most unhappy gift of England to Ireland. [Sidenote: =Reconciliation with the Pope.=] It was on his return from Dublin that King Henry met the legates of Alexander III. at Avranches, in Normandy, and, on swearing that he had neither planned nor consented to the murder of Becket, was taken into the Pope's favour, and received complete absolution. In return, he promised to go on a crusade, and swore that he would support Alexander against his enemy the Emperor Frederic I. He also consented to annul the Constitutions of Clarendon, but did not make any formal surrender of the principles on which they rested--the right of the State to deal with ecclesiastical persons guilty of secular offences. Thus ended the tragedy of Becket's strife with the king; the archbishop had obtained by his death what he could never win in his life, and the question between Church and State was left open, instead of being settled, as had at first seemed likely, in favour of the king.