The fourt option is: All time periods must be studied because no one period will cover all the themes. This is because the whole history of humanity is interrelated, many cultures and their emergences, as well as their outcomes, are interrelated, even each era is told differently by different cultures, historians and contemporary kings; and since history is a product of the data that each person, with his personal way of seeing the world, it is necessary to analyze a single era with sources from various historians and regions, in order to obtain the most veridical version of a only event.
