King
Henry IV of Castile married
Joan of Portugal, daughter of King
Edward of Portugal and the youngest sister of King
Afonso V of Portugal, on 21 May 1455. Seven years later, on 28 February 1462, Joanna was born at the
Royal Alcazar of Madrid. Her birth was celebrated across Castile with street celebrations, banquets, and bullfights. On 9 May 1462, she was officially proclaimed heir to the throne of Castile and created
Princess of Asturias.
Disputed heir to the throne In 1464,
Beltrán de la Cueva, a royal favorite, was awarded mastership of the
Order of Santiago, angering a faction of the Castilian nobility headed by
Juan Pacheco,
Alfonso Carrillo de Acuña, and
Pedro Girón. Desiring to depose Henry IV, undermine the rights of Joanna, and establish her half-uncle,
Infante Alfonso, on the throne, Pacheco and his followers circulated rumors that Infanta Joanna was actually the child of Beltrán de la Cueva. Henry's opponents soon began referring to the infanta as
"la Beltraneja", a mocking reference to her supposed illegitimacy. In September of 1464, Pacheco assembled his allies at
Burgos and published a manifesto condemning Henry IV's mismanagement and the excessive privileges granted to Beltrán de la Cueva. Formally alleging that Joanna was illegitimate and fathered by Beltrán, they demanded, among other things, that Henry recognize Alfonso as his heir. Henry yielded to the demands of the nobles and designated Alfonso his successor, with the stipulation that the infante eventually marry Joanna to ensure that they both would receive the crown. However, Henry hesitated to fulfill all of the magnates' wishes, especially with regards to government reform, causing relations to sour. In February 1465, he renounced Alfonso as his heir, commanded Beltrán to mobilize a royal army, and ordered Infanta Joanna, Queen Joan, and his younger half-sister
Isabella to be moved to
Segovia under heavy guard. Civil war broke out in June 1465 after Carrillo, Pacheco, and other agitators conducted a ceremonial deposition-in-effigy of Henry outside the city of Avila and
crowned Alfonso as a rival king. Around this time, Henry's opponents began to contest Joanna's legitimacy on the grounds that her parents never received the necessary papal dispensation for marriage within four degrees of consanguinity. In 1467, the nobles clashed with Henry's forces at the
Second Battle of Olmedo, which concluded as a draw. After rebels captured Segovia in 1467, a six-month truce was agreed to that arranged for the royal treasury and jewels to be returned to Henry's safekeeping in exchange for Joanna's mother, Queen Joan, to live at
Archbishop Fonseca's castle as a guarantee. While there, Queen Joan had an affair with Fonseca's nephew and bore two sons. Her indisputable status as an adulteress would later serve to weaken Henry IV's bargaining power. Alfonso died suddenly at the age of fourteen in July 1468. His claim as heir to the throne of Castile was inherited by his sister (Joanna's half-aunt),
Isabella. However, support for the rebels had begun to wane, and Isabella preferred a negotiated settlement to continuing the war. In September 1468, she met with her elder half-brother Henry at
Toros de Guisando and they reached a compromise known as the
Treaty of the Bulls of Guisando. The treaty stipulated that the war would stop, King Henry would name Isabella his heir presumptive instead of Joanna, and Isabella would not marry without her half-brother's consent, but he would not be able to force her to marry against her will. Henry also promised to obtain a divorce from Queen Joan. Because of Henry's affection for the Infanta Joanna, there were concerns about his actual willingness to relinquish her rights and he was accused of intending to evade the terms of the compromise. Outraged at the Treaty of Guisando, a faction of the nobility led by the powerful
Mendoza family began rallying for Joanna's cause.
Íñigo López de Mendoza, 1st Count of Tendilla, who had been appointed guardian of Joanna by Henry in 1465, distributed a letter to Castile's most powerful barons condemning the settlement and issued a formal protest to Pope Paul II. Following negotiations with Pacheco's rival party, the two factions agreed to a double marriage in which Joanna would marry
Afonso V of Portugal's son and heir,
John, and Isabella would marry Afonso. As explained by
Nancy Stuart: However, Isabella refused to consent to the arrangement and instead married
Ferdinand of Aragon in 1469. Henry IV denounced the marriage and issued a proclamation stating that by marrying without his permission, Isabella violated the Treaty of Guisando and was therefore no longer his successor. Concerned that disinheriting Isabella would provoke the anger of
Aragon, Henry IV sought to ally
France for support defending Joanna's claim. In a double ceremony on 26 October 1470, Joanna was proclaimed legitimate heir to the throne and betrothed to
Charles, Duke of Berry, brother of
Louis XI. On 8 December, Henry IV wrote to Charles urging him to dispatch troops to Castile. Charles, in conflict with Louis and disturbed by reports that Joanna was illegitimate, ultimately chose not to. In summer 1471, Charles sent an envoy to
Pope Paul II requesting to dissolve his betrothal to Joanna. After a few unsettled arrangements, which included French and Burgundian princes, Joanna was promised in marriage to her maternal uncle, King
Afonso V of Portugal, who swore to defend her (and his own) rights to the Crown of Castile. == Throne claimant ==