What reasons led to feudal fragmentation in western Europe?

There are several reasons for feudal fragmentation – political, military and economic.

The states of the early Middle Ages were rather weak, therefore they often disintegrated into possessions after the death of another significant ruler, for example, in France, King Charlemagne died in 814, and already in 843 the kingdom was divided and began to split further into smaller principalities.

Subsistence farming can be considered an economic reason.

The military reason was the need for defense against the raids of the Arabs, Vikings and Hungarians. She was often transferred to the local authorities, and she built castles, such was the senior organization of labor and military service. A feudal staircase of dukes, barons and knights appeared.