“Population” in the Italian Treccani encyclopedia is the “the group of people of a given locality, considered as a whole and in numerical extension.” From the biological standpoint, it refers to a “group of individuals of a given species occupying a defined geographical area, and isolated at various levels from similar groups of the same species.” The term originates from the late Latin population -onis which in turn comes from popŭlus, or “people,” and indicates the process of populating a territory. “Population” therefore underlines the dynamics of the concept of people and its expansion over time. According to Peter Turchin (2003, 3), population dynamics studies how and why a population varies in space and time. In addition to its increase or decrease, of course, stability may also be reached.

Fernand Braudel reflected on this essential component of human history, and titled part of his work “Weight of numbers.” Indeed, he began his trilogy Civilization and Capitalism: 15th– 18th Centuries (1960) with the consideration of population in its biological aspects, describing various human facets that are intrinsically biological: births, nutrition, diseases, life spans and deaths: the elements that compose “material life” as opposed to the market and capitalism. Like all living species, human beings exist in the physical interaction of energy and matter with the environment. Since the mastery of fire hundreds of thousands of years ago, this interaction comes about through techniques and technologies to obtain what is necessary for the species, and is part of the network of relationships between living beings and inanimate matter that we call ecology. Population dynamics is based on three components: births, that is, procreation, migrations and deaths. The process of procreation ensures continuity between generations and the maintenance of humanity on planet Earth. Historians and other social scientists generally do not consider it. It was the Annales school, to which Braudel belonged, that began the historical reconstructions of the European past describing how the essential needs of human life were met daily: nutrition, access to water, shelter from cold or excessive heat, possibility for rest and protection from pathogens. These are not platitudes to be taken for granted, but the fundamental basis on which human life can develop to make history.