prebends had been turned into hereditary fiefs. With feudal service went the various incidents of feudal tenure and a well-developed feudal jurisdiction of the lord over his tenants and of the greater barons over the less. In all this there is nothing to distinguish Normandy from the neighboring countries of northern France, and as a feudal society is normally a decentralized society, we should expect to find the powers of government chiefly in the hands of the local lords. A closer study, however, shows certain peculiarities which are of the utmost importance, both for Norman and for English history.
First of all, the military service owing to the duke had been systematically assessed in rough units of five or ten knights, and this service, or its subdivisions, had become attached to certain pieces of land, or knights' fees. The amounts of service were fixed by custom and were regularly enforced. Still more significant are the restrictions placed upon the military power of the barons. The symbol and the foundation of feudal authority was the castle, wherefore the duke forbade the building of castles and strongholds without his license and required them to be handed over to him on demand. Private war and the blood feud could not yet be prohibited entirely, but they were closely limited. No one was allowed to go out to seek his enemy with hauberk and standard and sounding horn. Assaults and ambushes were not permitted in the duke's forests; captives were not to be
