End of Feudalism
  I believe the 3 most important factors for the decline of feudalism were:
1.       Magna Carta
2.       The Crusades
3.       The Black Death
because when the Magna Carta was signed everyone was equal, especially the kings. Also they have the crusades because since they have lost their holiest land. Then Black Death came since all the serfs gained their skills and the manor system fell apart, so they were free from working at the knight's manor.
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