The Assize of Northampton in 1176 was, as has been said, a repetition in stronger terms of the Assize of Clarendon. It is moreover interesting, as giving a notion of the duties of the itinerant justices, who on this occasion were six in number. Not only was the examination of crimes in their hands, but they had to arrange the law with regard to tenure of land, reliefs of heirs, dowers of widows, and other such matters, and to exact fealty from all classes of the commonwealth, and to see to the complete destruction of private castles, and the secure guardianship of those of the crown. These latter points were probably rendered necessary by the Rebellion of 1174. The same feeling of mistrust of his feudal barons which dictated these precautions was the cause of two other measures of this reign. The military service of the tenants in chief was changed into a money payment called scutage. This money enabled the King to hire men for his foreign wars, and to dispense with the service of his barons; while, by the Assize of Arms in 1181, the national militia of England, the old _fyrd_ of the Saxons, to follow which was one of the duties of the _trinoda necessitas_, was reorganized, and the arms required of each class in the country carefully defined. [Sidenote: Henry’s importance in Europe.] [Sidenote: Closing troubles with his sons and France.] At the same time that Henry was thus organizing his authority in England, his position in Europe was a great one. Two of his sons were married or betrothed to daughters of the King of France. Of his three daughters, the eldest was the wife of Henry the Lion of Saxony, the rival of Frederick Barbarossa; the second, Eleanor, was Queen of Castile; the third, Joanna, though still a child, was taken to Sicily as the bride of the Norman king of that country, which at this time was the dominant power of the Mediterranean. His importance indeed was such that he seemed of all the kings in Europe most firmly seated on his throne, and was selected on account of his power and character, as well as for family reasons, as arbitrator between Alphonso of Castile and his uncle Sancho of Navarre, and as the strongest ally to whom Henry the Lion could have recourse when he was stripped of his German possessions. This befell him in consequence of his desertion of Frederick Barbarossa before his invasion of Lombardy, which terminated in the great battle of Legnano. But in the midst of his greatness there were two dangers constantly besetting Henry; on the one hand was the King of France, on the other were his own children. Not only did the great power of a feudatory naturally excite the French King’s jealousy, Henry had pursued a crooked policy with regard to the marriage of his sons; he had refused to surrender to Louis the Vexin and Bourges as he had promised to do upon their marriages. There was thus a constant opportunity for quarrel. On the other hand, with regard to his sons, his measures had been still more unfortunate.