Social, Economic and Cultural Transformations in the Portuguese Urban System* zyxw JORGE GASPAR AND CHRIS JENSEN-BUTLER Introduction The growth and recent development of the Portuguese urban system presents a number of interesting characteristics. In the following, special attention is given to the development of the system in the period 1960-89, the developments of the period being related to the history of the Portuguese urban system and to changing Portuguese external relations, which have throughout history exerted considerable influence on the development of the urban system. Against this background the changing determinants of urban system growth and differentiation are identified. Defining the urban system The principal cities and towns of Portugal can be seen in Figure zyx 1. The Portuguese urban system is the result of a long process of development having roots which go back to antiquity. However, the main period of urbanization in Portugal arrived very late, after the second world war. This urbanization was based upon three major growth vectors, which affected fundamentally the development of the system. The first vector was the process of urban concentration of population, related to the exodus from rural areas and the growth of the two main conurbations of Lisbon and Oporto. The second vector was related to the way in which the Portuguese population in fact became urban. Many Portuguese urbanized abroad through large-scale emigration to a number of countries, especially France, where about 500,000 Portuguese still live, mainly in Paris. This foreign urbanization slowed the growth of the Portuguese urban system outside of the conurbations. The third vector was the process of industrialization in rural areas, which developed rapidly during the 1960s, resulting in the phenomenon of diffslse urbanization. These vectors imply that a simple concept of urban centre cannot be applied in the Portuguese case. A broader concept of urban area must be developed. The present analysis deals with the urban system of continental Portugal; the island archipelagos are not included. The main statistical unit used throughout is the concelho, *The assistance of Eduarda Pires and Jorge Malheiros in the preparation of this paper is gratefully acknowledged, as is financial support from the Gulbenkian Foundation in the framework of a broader project on new urban and regional trends.