Afonso's grandfather
Afonso V of Portugal had sided with
Joanna la Beltraneja, who was a rival for the throne of
Castile against her half-aunt, Queen
Isabella I of Castile. She was never considered legitimate and, when the king was dying, no one took her as a serious contender for the crown. Isabella was due to inherit the crown, but Afonso V was keen to interfere with the succession in Castile. In 1475 he married his niece Joanna, whom he considered the legitimate heir to the crown. Since her adulteress mother was his own sister, Afonso V had not only ambition, but the family honour to protect. He proclaimed himself King of Castile and León and prepared to defend his wife's rights. King
Ferdinand and Isabella, however, won the war of succession and, as part of the
Treaty of Alcáçovas, signed in 1479, it was agreed that their eldest daughter
Isabella would marry Afonso. Isabella was also to come with a very large dowry that in practice represented the war compensation obtained by Portugal. In 1480, Prince Afonso, who at that time was five years old, went to live in the town of
Moura with his maternal grandmother,
Beatrice. In the early months of the following year, his future wife, the ten-year-old Isabella, joined him and lived there for about two years. The wedding, by
proxy, took place ten years later in the spring of 1490 in
Seville. On 19 November of that year, Isabella arrived in
Badajoz where she was welcomed by Afonso's uncle, Manuel, the future King
Manuel I of Portugal, whom she would eventually marry six years after her husband's death. Afonso and Isabella were reunited in
Elvas on 22 November and, on the following day, Isabella met her mother-in-law, Queen Eleanor, in the Convento do Espinheiro in
Évora, where the court had gathered to ratify the marriage that had been celebrated earlier in Seville. This wedding had the blessings of both Kingdoms. The queen of Castile, whose mother and nurse were Portuguese, wanted to strengthen the ties with Portugal, and, at the same time, this would allow her to "keep an eye on and control the steps of her eternal rival, Joanna la Beltraneja", through her daughter. ==Death==