What factors contributed to the development of feudalism and manorialism

I don't know much about the feudal system, but the manorial system was when the lords had knights that had land, and the serfs weren't slaves but, they weren't free either, but they were used by the lords to farm their land, the serfs got their own land for their own food and such, but the lord had an obligation to protect his serfs in times of crises. 

He made the polygraph too,but thomas edison was not falsely credited for the light buld