The evolution of settlement and colonization during the Middle Ages is of historical importance from many points of view. It is associated with three great phases of development–three essential chapters in the history of the nations of Europe.

Settlement on the land helped to bring about that mingling and stratification of the peoples from which the European nations sprang. To say that all peoples were once in restless motion and that their lines of conquest or migration have determined the division of the land among them is not enough. For not all these movements affected the foundations of agrarian society; although some conquests which merely introduced a new ruling class–like the Norman Conquest of England—yet left their mark deep in the national life of the conquered territory. The movements of the peoples from which the states of the European world arose were only in part movements which transferred the use of the land to new hands on a large scale. But such transfers must be kept in mind; as must others of a more peaceful sort—migrations and transplantations and resettlements of social groups. Governments showed themselves solicitous, now for a denser population in some given area, now for the raising of the general level of agricultural production. Where land was the main form of property its owners would seek to add to its utility by closer settlement. The rise of commercial and industrial centres would increase the demand for agricultural produce. As a result there might be extensions of existing population groups, or migrations of groups. And such developments might be just as important for the formation of the basic strata of European society as the direct seizures of territory by conquering hosts and the crowds who followed in their train.