I would agree with pohnpei397 with regard to the fall of feudalism. There were several reasons for the downfall of feudalism. It was a major change to the way of life, most especially for the very poor. They barely survived (and often did not), worked to death to serve the powerful and mighty, kept from moving up economically because of the lack of work available to them. With the plague and the enornmous loss of people to support a feudal system, it fell apart. It was a "morally bankrupt" system, as Chaucer showed to some extent in The Canterbury Tales...in particular with the Church. There was no need to allow the peasants to improve their lives because controlling them was so much easier when they depended so much on feudal lords, and cheaper because lords didn't lose much to keep them . With the fall of feudalism, Europe advanced in large part due to an emerging middle class.
Another part of the Hundred Years War that affected Europe was the ensuing peace that arrived at its conclusion. It is easier to make money in peace time, especially when money is not being spent on advancing an army and paying to keep it going.
These things changed the face of Europe at an amazing rate.