What effect did the bubonic plague have upon Europe and later the beginning of the Renaissance?
One effect was to break the power of the feudal system of Europe.
The bubonic plague created a shortage of labour. So many people died that there was a sever shortage of peasants to work the land.
Peasants that had previously had no power or leverage now could make demands on the royalty and land owners.
The peasants could now travel move to the cities. This created a more fluid social structure. People who were not part of the nobility were able to use their skills and intelligence to create jobs, and new niches in society. Peasants were no longer virtual slaves tied to the land. The bubonic plague had provide the means to freedom for many of the peasants.
In England, Holland and Italy the ruling classes adapted to the more fluid social structures. There was a still a caste system of royalty and commoners but the commoners had much more freedom and opportunities than before the plague hit Europe.