Answer:
Feudalism grew out of the class society of the late Carolingian Empire. The Frankish kings originally based their power mainly on the annual campaigns. The fighters were rewarded with part of the field gains. When all the desirable territories had been incorporated under Charlemagne, the king had to find another way to bind his nobles to him. Moreover, the empire had grown far too large to be run efficiently. Because of the primitive means of communication, he was forced to travel around in order to enforce his authority and "consume" his taxes on the spot, because they were often paid in kind. He therefore needed local representatives: officials. From this class arose the peerage.