N/A

On one hand, it would probably mean that science/technology advance quicker, since there would be more people to get geniuses out of. On the other, the overpopulation would lead to worse overall sanitation and maybe to faster colonization, as there would be more people willing to get out of Europe. Also, the fact that the relative population of Europe would be larger when compared to that of the Muslim world (not sure if this is the case, but I think Europe was affected much more than Middle East / North Africa) might play a role in the Reconquista and similar processes.
 
Some other reason would have to be found for a population crash, British agriculture couldn't support more than about 6 million people until about 1800. This is one reason behind the black death in the 1350s and the great plague in the 1650s was unsustainable population peaks. Undernourishment and overcrowding is a recipe for epidemic.
 
Is there any way to avoid the Black Death, though? I mean, as I learned it, it was more an inevitability than an avoidable crisis. How exactly would the Death have been avoided? The answer actually changes a lot depending on how it happens.
 
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