The colonization of the Atlantic world is generally considered to be an unprecedented and completely original phenomenon. This view is erroneous, however, since colonies existed in the eastern Mediterranean or Levant at the end of the Middle Ages. It was there that the technique of colonization which spread across the Atlantic world originated. The study of medieval influences on colonization in the Atlantic zone, i.e. America and Africa, opens up a new field of historical research and modifies the traditional perspectives from which we are accustomed to examine relations between the Old and New Worlds. Such a study, moreover, implies a conception of colonial history different from the old "external" conception. This point requires some explanation.