The « population size » variable offers one measure, among others, of the impact of foreign exchanges upon a région. In the XVth and XVIth Centuries western Andalusia had strongly increased and diversified its exchanges ; did the opening up of the American continent transform the region's economic System ? The population statistics for the cities and villages depending on Seville — its lands — indeed numerous from the beginning of the XVth contribute to a preliminary answer. These statistics are analyzed during three seperate periods, then taken ail together, until 1534 ; whereas diverse fluctuations mark the sub-periods, all villages and towns increase over the long term. Different « keys » are tested to identify the causes of these moveme...