These studies, written over a period of nearly thirty years, deal with two major themes: the reign of Alfonso X el Sabio (1252-84), and the development of the cortes of Castile-LeA(3)n, a characteristic example of the emergence of European representative parliamentary institutions. An introductory study on the integration of medieval Spain into western Europe in the late 11th century is followed by studies of Alfonso X's overall achievement, his innovations in the law and taxation, his relations with the church and the nobility, and the importance of the Cantigas de Santa Maria as an historical source for his reign. Seven other studies trace the origins and mature growth of the cortes from the late 12th century to the middle of the 14th, with particular attention to the documentary history of the institution.