“Si Possides Amicum, In Temptatione Posside Illum”: Alfonso VIII and Peter the Catholic

This chapter studies the relationship between Alfonso VIII of Castile and Peter the Catholic, the king of Aragon and count of Barcelona. From the time he ascended the throne in April 1196, Peter the Catholic was a faithful ally of Alfonso VIII. One can say that the alliance between the kingdom of Castile and the Crown of Aragon between 1196 and 1213 demonstrates continuity rather than change. The change is, perhaps, the extent of the stability and the strength of the alliance between Alfonso VIII and Peter the Catholic during almost twenty years. The battle of Las Navas de Tolosa was the highlight of the reigns of Alfonso VIII and Peter the Catholic. Alfonso VIII needed the victory in order to extend the Castilian borders at the expense of the Almohad Caliphate. Meanwhile, Peter the Catholic used his collaboration in the victory to legitimize his intervention in the Albigensian conflict.