20. =State of Ireland.=--In the domain of art, Ireland was inferior to no European nation. In metal-work, in sculpture, and in the skilful illumination of manuscripts it surpassed them all. It had no mean school of music and song. In political development it lagged far behind. Ireland was still in the tribal stage, and had never been welded into unity by foreign conquerors, as Gaul had been welded into unity by the Romans, and as England had been welded into unity by the Normans. Tribe warred with tribe and chief with chief. The efforts of chiefs to attain supremacy over the whole island had always ended in partial or complete failure. The Danes had made settlements in Dublin, Wexford, Waterford, Cork, and Limerick, but though the native Celtic population was not strong enough to expel them, neither were they strong enough to conquer the Celts. The Church was as disorganised as the State, and there was little discipline exercised outside the monasteries. For some time the Popes and the Archbishops of Canterbury had been anxious to establish a better regulated Church system, and in =1154= Adrian IV.--the only Englishman who was ever Pope--hoping that Henry would bring the Irish Church under Papal order, had made him a present of Ireland, on the ground that all islands belonged to the Pope. 21. =Partial Conquest of Ireland. 1166--1172.=--Henry, however, had too much to do during the earlier years of his reign to think of conquering Ireland. In =1166= Dermot, king or chief of Leinster, having been driven out of his dominions, appealed to Henry for aid. Henry gave him leave to carry over to Ireland any English knights whom he could persuade to help him. On this a number of knights from South Wales, of whom the most important was Richard de Clare, afterwards known as Strongbow, flocked across the Irish Sea (=1169--1170=). They fought and conquered, and Strongbow, who married Dermot's daughter, gave himself the title of Earl of Leinster. The rule of these knights was a rule of cruelty and violence, and, what was more, it might well become dangerous to Henry himself. If feudal nobles established themselves in Ireland, they might soon be holding out a hand to help the feudal nobles who were Henry's worst enemies in England. When Henry landed in Ireland in =1171= he set himself to restore order. The Irish welcomed him because he alone could bridle the invaders, and the invaders submitted to him because they dared not resist him. He gathered a synod of the clergy at Cashel, and arranged for the future discipline of the Church. Unhappily he could not remain long in Ireland, and when he left it the old anarchy and violence blazed up again. Though Henry had not served Ireland, he had gained his own personal ends. He had frightened Strongbow and his followers, and had shown the Pope, by his proceedings at Cashel, that his friendship was worth having. [Illustration: Mitre of Archbishop Thomas of Canterbury preserved at Sens.]