Relations between Portugal and Castile in the Late Middle Ages – 13th-16th centuries
By Vicente Ángel Álvarez Palenzuela
e-Journal of Portuguese History, Vol.1:1 (2003)
Abstract: A study of the intense diplomatic relations maintained between the Portuguese and Leonese, afterwards Castilian-Leonese, monarchies throughout the Middle Ages. They were dotted with a series of agreements relating to the internal problems of each kingdom, the mutual relations and the general political situation in the Iberian Peninsula. These relations, except for specific moments of brief warfare, which were sometimes very serious, were friendly and familiar. This didn’t exclude the occurrence of frictions resulting from contrary interests. On both sides of the frontier very similar problems were faced: dynastic confrontations or rebellions of the nobility in which both monarchies usually collaborated closely. Castilian expansion and the resulting imbalance of power in its favour, was the cause of the gravest tensions.
Introduction: Relations between the Portuguese monarchy and the monarchies of Leon or Castile (the Kingdom of Castile was the historical continuation of the Kingdom of Leon) after the unification of the latter two kingdoms show a profundity, intensity and continuity not to be found among any of the other peninsular kingdoms during the Middle Ages, even though these were also very close. The bond between the two went far beyond merely diplomatic relations. The matrimonial unions between the two were so strong and frequent that it is possible to claim that both kingdoms were ruled by a single dynasty during the entire Middle Ages.
Despite this, any attempt by one or the other to unify both kingdoms was destined to failure, and more often than not, to harsh confrontation leading to prolonged resentment and suspicions which were difficult to overcome. The very close relations are, in my opinion, the result of a common historical, cultural, and mental identity, but also of an awareness of the differences between their respective personalities. I make this claim without wishing to give credit to nationalist viewpoints which I consider to be out of place and inadequate for historical analysis.