Titular King of Aragon, consort of Castile, and, by conquest, of Navarre. He was born in Sos (Aragon) on March 10, 1452, the son of John II of Aragon—widower of Queen Blanche I of Navarre—and Juana Enríquez, daughter of the Constable of Castile. He was the half-brother of Charles, Prince of Viana, and was born during a civil war the supporters of his brother and those of his father, who had usurped the Navarrese throne upon the death of Queen Blanche I in 1441. At six years old, his father—who ed him a preferential affection lacking for the children of his first marriage—invested him with the titles of Duke of Gandía and Montblanc, Count of Ribagorza, and Lord of Balaguer, titles that originally belonged to his brother. At ten, he was sworn as heir to the Crown of Aragon, which included Aragon, Catalonia, Valencia, Mallorca, Sardinia, and Sicily. He married Isabella of Castile on October 19, 1469, at the age of 17.
From an early age, he fully grasped the hazardous political climate in Europe and sided with the Beaumont party in Navarre against his half-sister Eleanor I and supported the Count of Treviño, who controlled Gipuzkoa from 1471 (Battle of Munguía).
In 1474, he became consort king of Castile and led the struggle against the supporters of Princess Joanna. Maintaining control of Gipuzkoa was essential to stop potential French intervention. Relying on the loyalty of San Sebastián, he sent royal envoys, Antón de Baena and Bartolomé de Zuloaga, to swear allegiance to the fueros of Gipuzkoa and the Cuaderno de la Hermandad on behalf of the queen. With his characteristic skill, he also pacified the powerful noble families. Once this was accomplished, he turned his attention back to Navarre. Ignoring Eleanor’s rights, both Ferdinand and his father, John II—who still claimed the title of king since Queen Blanche I’s death—reached an agreement in Tudela (October 2–4, 1476) by which Castile, to prevent French encroachment, stationed 150 lances in Pamplona. This effectively established, as historian Lacarra put it, "a true protectorate over Navarre," making the Treaty of Tudela a model for future similar agreements Castile and Navarre.
From this point onward, Ferdinand, exploiting the paralysis in Navarre caused by the ongoing conflict the Agramont and Beaumont factions since his father’s usurpation of the throne, intensified his interference, culminating in the armed conquest of 1512. His real control was established through the Count of Lerín and by deliberately maintaining the conflict rival factions. During these years, his dedication to Castilian affairs was total. The three Basque provinces supported Isabella. To consolidate this support, Ferdinand swore allegiance to the Fueros of Bizkaia in Gernika on July 30, 1476, on behalf of Isabella, who would do so later. Around this time, he began a romantic affair with the Biscayan Toda de Larrea, who bore him a daughter and was later abducted by Queen Isabella.
In 1479, the Castilian succession war ended in Isabella’s favor. That same year, upon the death of John II on January 19, Ferdinand ascended to the throne of Aragon, though this did not reduce his involvement in Castilian affairs. He assisted the queen in legislative reforms, especially in efforts to end the factional wars in Álava, Gipuzkoa, and Bizkaia.
Meanwhile, he tightened his diplomatic grip on Navarre under Francis Phoebus (1479–1483), who succeeded Eleanor I in 1479. Navarre could only hope for French assistance, as Eleanor’s will urged her grandson. The marriage of her successor, Catherine I, to John of Albret deepened the crisis. Despite seeking closeness with France, this alliance was disapproved by both the Beaumont supporters of Castile and some Agramontese. Crowned on January 12, 1494, with the help of troops sent by the Catholic Monarchs, John and Catherine agreed on the same date to marry their heir to a child or grandchild of Isabella and Ferdinand—further strengthening Castile and Aragon’s grip. The war with France for Italian dominance provided a pretext for continued pressure from 1495 onward; Ferdinand's intervention was framed as guaranteeing Navarre’s neutrality. At the same time, the war allowed him to challenge the authority of the Bishop of Bayonne over the Guipuzcoan parts of his diocese, which, as remembered, included the Bidasoa basin and parts of Gipuzkoa until the 1712 treaty. See Bayonne.
Widowed in 1504 by Isabella’s death, Ferdinand married Germana de Foix in October 1505, sister of the Viscount of Narbonne and claimant to the Navarrese throne and the Foix inheritance since Eleanor I’s death. This claimant would be used by the French king to challenge sovereignty over Béarn, while Ferdinand reinforced his annexationist policy by maintaining loyal ties with the Beaumont party. In 1507, due to Queen Joanna of Castile’s mental instability and the death of Philip the Handsome, Ferdinand was reinstated as regent of Castile. Despite focusing on his rivalry with France over Italy, he remained committed to establishing a definitive border Gipuzkoa and Labourd. A dispute in 1510 over the Hendaye area would last until 1624.
After the defeat at Ravenna (April 12, 1512), armed with papal bulls and citing Catherine I’s alliance with France, he proceeded to annex Navarre. On July 20, 1512, his troops entered the kingdom, and he d himself “Custodian of the Crown and Kingdom of Navarre,” later proclaiming himself King of Navarre in August, invoking the bull Pastor ille coelestis. With this title, which he held until 1515, he appointed Don Diego Fernández de Córdoba y Arellano, Marquis of Comares and commander of Los Donceles, as Viceroy of Navarre on December 17 of that year.
Historian Campión, who studied Ferdinand’s political and military strategy for consolidating his conquest (Después de la conquista, Euskariana VII, pp. 359–437), provides the following insights:
“Once Navarre was conquered, Ferdinand naturally focused on securing his prize. He emulated the wise policies of prudent rulers in similar cases. The Aragonese king, adept in both cunning and force, freed himself from dependence on the factional wars that had long dominated the Pyrenean crown since the Prince of Viana. Using diplomacy to avoid reigniting civil war or fostering a reconciliation that could rally the country against the intruding monarchy, he understood that only time would solidify his conquest. Though aging and ailing, he faced a people—proud, stubborn, energetic, and resentful of humiliation—who were momentarily defeated by years of civil war. The conquest, swift and tactically brilliant, was met with little resistance and bloodshed. For the Beaumont party, it felt like a dream; for the Agramontese, a nightmare—though not as dreadful as feared.”
Within two months, the crown—historically passed legally or with dignity—was seized by force. National disillusionment spread after John of Albret’s failed attempt to retake the kingdom (Sept–Dec 1512). Ferdinand took advantage of the moment to assert irreversible facts and erase the stain of usurpation by presenting himself as king of all—both Beaumont and Agramont parties.
“He needed to appear affable, benevolent, conciliatory—but calculatedly so—offering both favors and deterrents to ensure that his former enemies feared him without labeling him vengeful, and his allies trusted him without calling him ungrateful.”
While intimidation was part of his strategy, he preferred warnings over premature harshness. Nevertheless, violence, coercion, and abuses occurred—though, compared to the standards of the time, they seemed less grave. A few dramatic cases, like the destruction of the Garro Valley and burning of Mongelos, sent a clear message to the Basques of Lower Navarre. In Upper Navarre, harsh treatment befell Don Pedro de Rada, governor of Murillo, who raised the flag of the legitimate monarchs. He was tortured and killed in Tafalla.
“After taking steps to retain control of his conquest, Ferdinand focused on governance, with the cooperation of the locals. The Beaumontese realized too late that they had ed the mistake of the horse in the fable, who let a man ride it to avenge the deer, only to end up enslaved. Being under Ferdinand, the most powerful monarch of the time, was not the same as being under a weak local monarch. They sought to safeguard their traditional liberties and even expand them.”
Ferdinand supported this aim to avoid unrest and to establish legitimacy. He allowed the regular convening of the Cortes, seeing them as a way to become the king of all, rather than a factional monarch. Although initially dominated by Beaumontese, he knew they would eventually lose that bias once dynastic threats subsided. Unlike Castilian rulers later during the Comuneros revolt, Ferdinand never sought to diminish the representative power of the Cortes. He summoned them to swear allegiance and governed through them.
“A lesser monarch would have only demanded loyalty and dismissed the assembly. Ferdinand, shrewd and daring, did more. Though he ruled justly until his conquest was legally secured, he did not act impeccably. He broke oaths, violated the fueros, and established a precedent for both reparations and recurring violations. Some wrongs were never redressed—for instance, placing the kingdom’s castles in foreign hands.”
The first Cortes convened in Pamplona from March 13 to 24, 1513. These Beaumontese Cortes swore loyalty to Ferdinand in exchange for his promise to uphold the Fuero. His representative promised pardon for all Agramontese who had not sworn allegiance. With the Sixth Merindad occupied, the Lower Navarrese nobility submitted on June 5, 1513. The second post-conquest Cortes met on January 29, 1514, and the final ones on March 15, 1515, with Ferdinand still calling himself King of Aragon and Navarre.
In 1515, having lost hope of having a son with Germana de Foix to maintain Aragon and Navarre separate from Castile, and anticipating his grandson Charles’s rise, Ferdinand incorporated Navarre into the Crown of Castile on June 11, 1515, “preserving the fueros and customs of said kingdom.” He died in Madrigalejo on January 23, 1516, just as Marshal Pedro de Navarra was launching an attempt to reconquer the kingdom. In his will, Ferdinand left the kingdom of Navarre to his daughter Joanna the Mad and his grandson Charles.