This article describe about Medieval Demography, which is estimates and seeks to explain the number of people who were alive during the Medieval period, population trends, life expectancy, family structure, and related issues. Medieval Europe Population and Demography info, values and graphs. Major medieval cities in Europe. Most populous countries and cities of the Middle Ages. The science of medieval demography relies on various lines of evidence, such as administrative records, wills and other types of records, archaeological field data, economic data, and written histories.