John, Prince of Asturias

John, Prince of Asturias and Girona (Juan; 30 June 1478 – 4 October 1497), was the only son of King Ferdinand II of Aragon and Queen Isabella I of Castile, and heir apparent to both their thrones for nearly his entire life.

Early life
The only son of the Catholic Monarchs, John was born in Seville on 30 June 1478. At the time, his parents were involved in the War of Castilian Succession against Isabella's niece Juana la Beltraneja, wife of King Afonso V of Portugal.

John's birth helped consolidate Isabella's position as a sovereign. At the time of his birth, he had one elder sister Isabella; his younger sisters were Joanna, Maria, and Catherine.

The Catholic monarchs won the war against the King and Queen of Portugal. To negotiate a peace settlement with Isabella, King Afonso sent Infanta Beatrice, Duchess of Viseu. The two women met in March 1479. Beatrice was Afonso's sister-in-law and Isabella's maternal aunt. By terms of the treaty they eventually negotiated, the former Queen of Portugal (her marriage having been annulled by the Pope) was given two options: she could either wed Prince John, waiting 13 or 14 years until the prince was old enough to be married (by which time Joanna herself would be at least thirty) or she could enter a convent; either way she was to give up her claim to the throne.

Childhood
Isabella I was quite an attentive mother for such a busy queen. John, being her only son and of delicate health, had a special place in her heart, and she referred to him affectionately as 'my angel' even when he was being reprimanded by her. Isabella and Ferdinand attempted to ensure the sickly prince's well-being through prayer, charity, and careful oversight of his health. John's wetnurses were Maria de Guzman, a member of the powerful Spanish House of Mendoza, and Juana de Torres. The latter stayed by the prince's side well into his adolescence, possibly as a result of his frail health.

John's paternal grandfather, King John II of Aragon, took close interest in the infant prince; he warned his son Ferdinand that the prince should not be tutored under one grandee, a member of the nobility, as they would have far too much influence over the boy.

In 1492, Columbus named the newly discovered island of Cuba as Isla Juana in deference to Prince John, at that time the heir apparent. In 1494, Columbus's sons, Diego and Ferdinand, were brought to court to serve as John's pages.

Education
As heir to the throne, Isabella and Ferdinand paid special attention to John's education. The young prince received his early education predominantly in theology under the tutelage of Dominican Fray Diego Deza, a devout Catholic scholar. His education broadened in the early 1490s when Isabella asked Italian humanist Peter Martyr d'Anghiera to serve as his personal tutor.

Isabella, seeking to prevent her son from growing up coddled and willful, invited the sons of aristocrats to live at court and serve as peers and role models for the young prince. John and his companions received instruction in various disciplines such as riding, jousting, hunting, music, and poetry. John demonstrated a natural aptitude for music and played the flute, violin, and clavichord.

Marriage plans
During his early years, Isabella and Ferdinand considered Princess Catherine of York, a daughter of King Edward IV of England and his wife Elizabeth Woodville, as a potential wife for John. Although a marriage contract was signed in 1478, the union never took place. Other proposed candidates were Anne of Brittany and Catherine of Navarre.

In 1494, King Charles VIII of France laid claim to the throne of Naples and launched an invasion of Italy. Because Naples belonged to a lesser branch of the House of Trastámara, his invasion directly threatened Aragonese interests. This prompted King Ferdinand to began building a coalition, known as the Holy League, against France. Seeking Emperor Maximilian I's participation, Ferdinand engaged in negotiations for dynastic marriages between the Habsburg and Spanish royal families, aiming to seal the prospective alliance between the Holy Roman Empire and Spain.

On 20 January 1495 in Antwerp, terms for a double marriage were agreed on: John would marry Maximilian I's daughter, Archduchess Margaret of Austria, and his sister, the Infanta Joanna, would marry Maximilian's son, Archduke Philip the Handsome. The agreement was officially ratified on 5 November in Malines.

Marriage
Infanta Joanna sailed from Spain to marry Philip the Handsome in late 1496, accompanied by a grand fleet. The same fleet returned months later carrying Philip's sister, Margaret of Austria. Margaret, aged sixteen, had already been betrothed once to Charles VIII, but the marriage treaty was renounced. Her engagement to the Prince of Asturias seemed doomed when the ship carrying her to Spain hit a storm in the Bay of Biscay. In haste, she wrote her own epitaph should she not reach Spain. "'Here lies Margaret, the willing bride, Twice married – but a virgin when she died.'" However, Margaret arrived in Spain safely and married Prince John on 3 April 1497 in Burgos Cathedral. Although the marriage was a political one, the young couple quickly became devoted to each other. Apparently, the amount of time they spent in bed made the court physicians uneasy about the Prince's health.

Death
In September 1497, John's fragile health prevented him from joining his parents and sister, Infanta Isabella, as they journeyed to the Portuguese border for her wedding to Manuel I. Instead, he and Margaret travelled to Salamanca, marking their arrival with a ceremonial entry. The next week, after receiving reports that John's condition was worsening, Ferdinand rushed to his son's bedside.

On 4 October 1497, John died, possibly of tuberculosis or smallpox. His dog, a lurcher called Bruto, had whimpered as he died, then stayed next to his coffin throughout the vigil in Salamanca's main church. John's devastated mother would later keep the dog next to her, as if to keep the memory of her beloved son with her. Six months later, on 2 April 1498, the Princess of Asturias gave birth to their only child, a stillborn girl.

Consequences
John's death was followed closely by that of his sister Isabella in 1498. Her only child, Miguel de la Paz, died in 1500. The Spanish kingdoms passed to his younger sister Joanna, her husband Philip the Handsome, and their Habsburg descendants. Philip had himself and Joanna declared as 'Princes of Castile' which her parents saw as disrespectful towards his deceased brother-in-law.