[Resumen extraído de la fuente original] 

The article reflects on the historical concept of frontier and our present idea of it. It focuses on the importance of the frontier in the dynamics of the feudal system in the Iberian peninsula and explores the role played by the crown. The hypothesis here is that the configuration of a coherent socio-political space spans differing yet chronologically juxtaposed phases. Four phases in the process of delimiting the political space are distinguished—military, socio-economic, cultural and political-administrative. New elements combine with the existing ones until a new entity takes shape: the political-administrative system, which is analysed here. In analysing this evolutionary process, an ensemble of Arab historiographic sources, Christian chronicles and fueros and secondary sources, has been used.