The answer is reason.
Philosophers of the Enlightenment believed that answer can be found
through reasoning. There were two types
of reasoning during that time. You have
rationalism that relies on deduction and Empiricism which deals with
experience. It took root due to the liberal atmosphere at the time.
This historian would be using the skill of "comparative analysis," since he or she is comparing a wide variety of sources to draw a conclusion between them as a group.
The black death effect society by a series of religious, social, and economic upheavals. it was one of the most devastating pandemics in human history, peaking in europe between 1347 and 1350 with 30% to 65% of the population killed.
hope this helps, God bless!
The Prime Meridian, divides the Earth at 180 degrees longitude.
