Castilian War of Succession Summary

  • Last updated on November 11, 2022

The struggle for the Castilian throne determined the future development of the Iberian Peninsula.

Summary of Event

King John II of Castile (r. 1406-1454), during a long and disturbed reign, married twice. First, he married Maria of Aragon, who provided the heir to the throne, Henry (the future Henry IV). Then he married Isabella of Portugal, who gave him a second son, Alfonso, and a daughter, Isabella. Castilian War of Succession (1474-1479) Henry IV of Castile Joan Isabella I Afonso V John II (king of Castile and León) Henry IV (king of Castile) Alfonso (prince of Castile, son of John II) Afonso V (king of Portugal) Joan (daughter of Henry IV) Cueva, Beltrán de la Joan (daughter of Henry IV) Louis XI (king of France) Isabella I (queen of Spain) John II (king of Portugal) Ferdinand II (king of Spain)

Henry, in his turn, married twice. In 1440, he married Bianca of Navarre, but the childless marriage was annulled in 1453 on grounds of impotence. By then, Henry was negotiating a second marriage with Joan of Portugal, sister of the Portuguese king, Afonso V. Because of the couple’s consanguinity, Pope Nicholas V granted a papal dispensation at the close of 1453, which again referred to Henry’s impotence. Nevertheless, the new queen gave birth to a daughter, also named Joan, in February of 1462. In May, the nobility that were assembled in Madrid swore an oath of allegiance to the baby as Henry’s heir, and in July, the Castilian cortes (parliament) meeting in Toledo did the same.

To historians, Henry IV is an opaque figure. He had inherited from the previous reign a habitually unruly nobility. Henry sought to diminish the influence of the higher nobility by the promotion of new men of his own choice, among whom was his special favorite (privado), a young man named Beltrán de la Cueva. Rivals at court asserted that Beltrán was the real father of Princess Joan, who from her birth was derisively nicknamed “La Beltraneja” (the one from Beltrán). The libelous nickname was included in a manifesto drawn up in 1464, which, among a list of humiliating demands made on the king, required him to acknowledge his half brother, Alfonso, as his heir. Under duress, Henry agreed, but subsequently reneged.

There followed the extraordinary Farsa de Ávila Farsa de Ávila (1465) of 1465, in which a wooden effigy of the king was placed on a throne outside the walls of Ávila, to be insulted and then knocked to the ground, symbolizing Henry’s deposition. Thereafter, the rebels proclaimed Alfonso as “Alfonso XIII.” Civil war followed, but most of the kingdom remained loyal to the king. Henry’s victory over the rebels in August of 1467, followed by Alfonso’s death in July of 1468, restored a measure of authority to the king. These events provide the background to the succession struggle that followed Henry’s death in 1474.

After the Farsa de Ávila and before the tide had turned for him, Henry, overwhelmed by aristocratic faction-fighting, had turned for support to external allies, King Louis XI of France and Afonso V of Portugal. In September, 1465, Henry met with Afonso, and the latter offered military assistance in return for marrying Henry’s half sister, Isabella I, while Afonso’s son, John II (r. 1481-1495), would marry Henry’s daughter, Joan. Isabella rejected this arrangement, which presumably would have ended her days as a youthful dowager queen, and, following the death of her brother Alfonso XIII, she sought a reconciliation with Henry with the Pact of Los Toros de Guisando (1468) Los Toros de Guisando, Pact of (1468) , where he recognized her as his heir on condition that she not marry without his permission. Isabella favored marriage with Ferdinand II, son of John II of Aragon (r. 1458-1479), and in March, 1469, a surreptitious betrothal was negotiated at Cervera between the seventeen-year-old Isabella and Ferdinand, a year younger. Ferdinand subsequently made his way to Valladolid, where the couple was privately married (October 19, 1469). Henry, furious at being tricked, then proposed to marry Princess Joan to Afonso of Portugal, who was to bring forces into Castile to assist Henry against Isabella and her supporters, and to occupy the frontier-fortresses of Badajoz and Ciudad Rodrigo.

The following five years saw desultory fighting and much intrigue, with Isabella’s supporters dominating eastern and central Castile, while Henry controlled Asturias, Galicia, Extremadura, and parts of the south. Then, in December, Henry died, and sporadic civil strife, a feature of Castilian life for half a century, gave way to out-and-out war over the succession.

The initiative then lay with the Portuguese, and Afonso, rejecting the slur of illegitimacy cast at his future bride, offered himself as a chivalric champion going to the rescue of a young woman in distress—Joan was still only thirteen—and since she was also his niece, he secured a papal dispensation for the marriage from Pope Pius II (1458-1464). He believed that Joan enjoyed widespread support in many cities and that he had an active ally in Louis XI. Isabella, meanwhile, used every kind of diplomatic ploy to delay and deflect the anticipated invasion.

In April, 1475, Afonso invaded Extremadura with a force of five thousand cavalry, fifteen thousand infantry, and a siege train, and rapidly captured Salamanca, Arevalo, Zamora, and Toro. His strategy was to advance on Burgos, where he anticipated joining his French allies and advancing through the Basque country. Meanwhile, Joan had been spirited out of Castile and brought to Trujillo, where she and Afonso were formally betrothed (1475). The two then married at Plasencia, and the next day Afonso proclaimed Joan their rightful queen.

It has been suggested that had Afonso turned south, he might have quickly acquired a substantial part of Castile, but the preoccupation with reaching Burgos proved disastrous, since Ferdinand was able to place a joint Aragonese-Castilian force between Afonso and his objective, and to commence the siege of Burgos, since the expected French troops never materialized. The conflict looked as if it might grind to a stalemate, but with generous contributions from the Castilian church, Isabella was able to send raiders across the Portuguese frontier, leaving Afonso at Toro, unable to advance to Burgos or to defend his own kingdom. Burgos surrendered to Ferdinand in January, 1476, releasing troops to dispatch against Zamora. On March 1, 1476, a decisive Castilian victory at the Battle of Toro Toro, Battle of (1476) led to the fall of Zamora, forcing Afonso and Joan to return to Portugal.

Afonso had not given up, however. Leaving Prince John to rule in Lisbon, he set off for France in an attempt to rally Louis’s support. He remained in France from September, 1476, to November, 1478, and returned to Lisbon five days after his son’s coronation, only to discover his marriage to Joan had been annulled by Pope Sixtus IV (1471-1484) under pressure from Isabella. John returned the royal title, but Afonso was a mere cipher, dying in 1481 on the eve of abdication.

Isabella was now, indubitably, ruler of Castile, but a formal end to hostilities with Portugal called for long, hard bargaining, ending in the Treaty of Alcáçovas (1479) Alcáçovas, Treaty of (1479) . The Portuguese had wanted Isabella’s first-born son to marry the now-available Joan, but Isabella would have none of it. She still viewed Joan as a threat, for many had recognized her as Henry’s eldest child, and whatever her paternity, she was clearly a daughter of the House of Avis. Isabella demanded Joan’s close confinement in a nunnery. Joan did, indeed, enter the royal convent of Santa Clara-a-Velha in Coimbra, but her confinement was anything but strict. She came and went between her retreat and the royal court, and continued to style herself queen. Isabella fretted and protested, but both John and Portuguese king Manuel I (r. 1495-1521) were indifferent. Joan lived for nearly seventy years, dying in 1530, outliving her cousin, Manuel, by a decade, and her implacable enemy, Isabella, by nearly thirty years. Posterity, however, retains for her the opprobrious nickname bestowed upon her from birth.


Historians consider the years 1474 to 1479 to mark a transition between the anarchy of the early Trastamara period and consolidation under Queen Isabella I and King Ferdinand II. The conflict itself was once described as the most frivolous war in Portugal’s history. Had victory gone the other way and Castile and Portugal had been united, rather than Castile and Aragon, the history of the Iberian Peninsula and of much of Western Europe would have been quite different.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Edwards, John. The Spain of the Catholic Monarchs, 1474-1520. Malden, Mass.: Blackwell, 2000. This is the definitive monograph in English on the reign of the Catholic monarchs.
  • citation-type="booksimple"

    xlink:type="simple">Liss, Peggy K. Isabel the Queen: Life and Times. New York: Oxford University Press, 1992. This scholarly biography provides a detailed account of Isabel’s early life and struggle for the throne.
  • citation-type="booksimple"

    xlink:type="simple">Miller, Townsend. Henry IV of Castile, 1425-1474. Philadelphia: Lippincott, 1972. A popular biography of the enigmatic monarch.
  • citation-type="booksimple"

    xlink:type="simple">Phillips, W. D. Enrique IV and the Crisis of Fifteenth Century Castile, 1425-1480. Cambridge, Mass.: Medieval Academy of America, 1978. A reevaluation of Henry and his reign.
  • citation-type="booksimple"

    xlink:type="simple">Tate, B. T., ed. Fernando de Pulgar: Claros Varones de Castilla. Oxford, England: Clarendon Press, 1971. Tate prefaced his edition of this fifteenth century Castilian author with an introduction discussing the Castilian nobility, which played so great a part in destabilizing contemporary Castile.
  • citation-type="booksimple"

    xlink:type="simple">Weissberger, Barbara F. Isabel Rules: Constructing Queenship, Wielding Power. Minneapolis: University of Minnesota Press, 2004. A detailed analysis of how Isabel acquired power and retained it throughout her lifetime.

Oct. 19, 1469: Marriage of Ferdinand and Isabella

1580-1581: Spain Annexes Portugal

Categories: History