13. Two kingdoms, one crown (1460-1476)
By 1460 Pedro II felt strong enough to retaliate against those who had defied him. He was planning to undo all the reforms that had been imposed upon him and, again, he began to muster his forces to strike against his enemies. However, an unexpected bout of the Black Death killed him un August of that year. leaving his son Enrique (1444-1474) as heir.
Enrique III, who was fifteen years then, proved to be a quite resorceful king, although a bit too machiavelic and too sure about his capabilities. He began by making peace with his subjects, ratifying the changes and using his strenght and resources to improve the country. However, for the next ten years he had to deal with the rebellions León, which led to open warfare from 1460 to 1470. By that time, Enrique III had crushed the resistance and, with most of his leaderse dead, Leon had to surrender. From then on, Enrique stiled himself "King of Castille and Leon".
The king had secured his western borders by marrying Juana of Portugal and by meeting the Portuguese king, Afonso V; and supported the pretender to the Aragonese Crown, the future Pedro V, during the Aragonese civil war (1463-1471). Thus, everything seemed to be falling slowly into place, but for a problem: he lacked any male heir. To make it worse, his two brothers, Alfonso and Juan, had only daughters. Thus, when Enrique III named Isabel, the daughter of his brother Alfonso, his younger brother, Juan, and her daughter, Maria, felt slighted and began to conspire, using the fears of the nobility about the regal uses of trying to ger rid of the Parliament, somethuing that their pretender was not going to do (or at least they said so). As years went on and no male heir came, the tension in the kingdom gew and grew until the king died on 9 May 1474. After his death, Isabel was officially proclaimed heiress to the throne of Castile and created Princess of Asturias. Enrique III, during his lifetime, had the nobles of Castile and Leon swearing allegiance to her and promise that they would support her as monarch. However, when he died, some noblemen recognized Isabel as monarch, while others recognized her cousin Maria as the real queen, thus initiating the War of the Castilian Succession (1476-1477).
Isabel, who embodied the royal status of the annointed queen and the legality of the last will of Enrique III, had the support of King Afonso V of Portugal, and also the help of some of the high Castilian nobility: the Archbishop of Toledo, Alfonso Carrillo de Acuña; the mighty Marquis of Villena, Diego López Pacheco; the Estúñiga family. On the other hand, María was supported by Pedro VI of Aragon, who became her husband, and by most of the Castilian nobility and clergy: the powerful Mendoza family; the Duke of Medina Sidonia, Enrique Pérez de Guzmán. A Portuguese army entered Castile under the command of Afonso V on May 1476, and advanced to Plasencia, where Isabel was proclaimed queen of Castile and were married. From Plasencia, they marched to Burgos. There Afonso hoped to be able to unite with any troops sent by his ally, Louis XI of France. However, Louis backed from joining him, as he had a truce with Pedro VI and he was busy settling accounts with Burgundy.
Even worse, Afonso found fewer supporters in Castile than he expected, and changed his plans, preferring to instead consolidate his control in the area closest to Portugal. Pedro VI wasted little time concentrating his battle-hardened army in Tordesillas, and on July 15 marched against Afonso, who tried to avoid direct combat. Pedro, lacking the necessary resources for a siege, was forced to return to Tordesillas. Afonso V, considering its options, decided to withdraw to Zamora. This lack of aggressiveness debilitated his standing and Isabel's in Castile, and his supporters began to change sides. Supporters of Maria counter-attacked by gaining control of the lands of a significant portion of lands of the Marquisate of Villena, who was taken prisoner by Pedro VI and later on hanged by command of Maria, who also forfeited his lands. On December 4, Zamora rebelled against King Afonso, who was forced to flee to Toro, and, in January 1476, Burgos surrendered to Isabel.
In February 1476, the reinforced Portuguese army, left its base in Toro and marched against Pedro VI in Zamora. However, the Castilian winter hit hard the invading army, that was slowed down and then caugh by surprise by the Aragonese near of Alba de Tormes. After three hours of fighting under the cover of rain and nightfall, Afonso V withdrew to Portgual with part of his troops. The rest of his forces, along with his son Joao, perished on the battlefield.
The war was over and María was queen of Castille.