In the history of these cities a whole succession of geographic factors have in turn been active, each leaving its impress of which the cities become, as it were, repositories.
[Sidenote: Effect of a previous habitat.] The importance of this time element for a solution of anthropo-geographic problems becomes plainer, where a certain locality has received an entirely new population, or where a given people by migration change their habitat.

The result in either case is the same, a new combination, new modifications superimposed on old modifications.
And it is with this sort of case that anthropo-geography most often has to deal.

So restless has mankind been, that the testimony of history and ethnology is all against the assumption that a social group has ever been subjected to but one type of environment during its long period of development from a primitive to a civilized society.

Therefore, if we assert that a people is the product of the country which it inhabits at a given time, we forget that many different countries which its forbears occupied have left their mark on the present race in the form of inherited aptitudes and traditional customs acquired in those remote ancestral habitats.

The Moors of Granada had passed through a wide range of ancestral experiences; they bore the impress of Asia, Africa and Europe, and on their expulsion from Spain carried back with them to Morocco traces of their peninsula life.
A race or tribe develops certain characteristics in a certain region, then moves on, leaving the old abode but not all the accretions of custom, social organization and economic method there acquired.