What finally broke Europe out of the social structure it was in during the medieval era is known as the "Plague."
This is because the medieval era in Europe lasted between 500AD to 1400AD.
During this era, the emergence of the Plague, particularly the "BlackDeath" between 1347-1352 totally affected the social structure of Europe at that time.
As the population decreases, the feudal system was greatly affected.
Thus, the social structure of Europe was changed in the subsequent years.
