[MN 1135.] In the progress and settlement of the feudal law, the male succession to fiefs had taken place some time before the female was admitted; and estates being considered as military benefices, not as property, were transmitted to such only as could serve in the armies, and perform in person the conditions upon which they were originally granted. But when the continuance of rights, during some generations, in the same family, had in a great measure, obliterated the primitive idea, the females were gradually admitted to the possession of feudal property; and the same revolution of principles which procured them the inheritance of private estates naturally introduced their succession to government and authority. The failure, therefore, of male heirs to the kingdom of England and duchy of Normandy seemed to leave the succession open, without a rival, to the Empress Matilda; and as Henry had made all his vassals, in both states, swear fealty to her, he presumed that they would not easily be induced to depart at once from her hereditary right, and from their own reiterated oaths and engagements. But the irregular manner in which he himself had acquired the crown might have instructed him, that neither his Norman nor English subjects were as yet capable of adhering to a strict rule of government; and as every precedent of this kind seems to give authority to new usurpations, he had reason to dread, even from his own family, some invasion of his daughter's title which he had taken such pains to establish.