Excerpts from Books and Wikipedia
"Charles was the youngest son of Louis the Pious, and acquired the kingdom of West Francia in 843. . . . Charles's concession to hereditary fiefdoms can therefore be seen as another sign of the weakening authority of the Carolingian dynasty. The recognition of hereditary rights was significant on two counts. First, it was an important step in the development of feudalism, and granted magnates greater power over their own dominions and enabled them to form local dynasties. Secondly, the power of the king declined as the feudal lords became more independent of the crown and built up small territorial states of their won, which were often at war with each other. . . . With this system, the age of large empires, such as that of the Carolingian emperors, would be difficult to maintain." [1001 Days]