The war was in part prompted by the decrees of John II of Castile and his aide Álvaro de Luna that rents, that is taxes, from the town of Medina del Campo would be paid to his administration, rather than that of John II of Aragon, also of Navarre. The latter king invaded Castile, aided by his brother Alfonso V of Aragón. The Castilian king departed from Medina del Campo, and met the invasion at Olmedo, where he was successful. The infante (prince) Henry of Aragon, the younger brother of Alfonso and John, died of his wounds a few days later in Calatayud.
- Translated from Spanish Wikipedia
- Martin, José Luis (2003). Enrique IV. Hondarribia: Nerea. 84-89569-82-7.
- Valdeón Baruque, Julio (2001). Los Trastámaras. Madrid: Temas de Hoy. 84-8460-129-3.