This 1468 treaty ended the Castilian civil war by making Isabella heiress to the Crown of Castile, setting the stage for her eventual reign.
Key Facts
- Treaty signed
- 19 September 1468
- Title granted to Isabella
- Princess of Asturias
- Mediator
- Giacopo Antonio Venier
- Civil war began
- 1464
- Treaty voided by Henry IV
- 25 November 1470, Val de Lozoya
By the Numbers
Location
Cause → Event → Consequence
A civil war erupted in Castile in 1464 when a group of noblemen rebelled against Henry IV and symbolically dethroned him, replacing him with his half-brother Alfonso. After Alfonso's death in 1468, Isabella became the rebels' candidate. Preferring negotiation to continued conflict, Isabella sent Giacopo Antonio Venier as mediator, leading to preliminary talks at Castronuevo.
Signed on 19 September 1468 near the Bulls of Guisando in Ávila, the treaty between Henry IV of Castile and his half-sister Isabella ended the civil war. Isabella was recognized as heiress presumptive and given the title Princess of Asturias along with a large endowment. Joanna, Henry's daughter, was removed from the line of succession through the annulment of Henry's marriage.
Isabella's subsequent unauthorized marriage to Ferdinand of Aragon caused Henry IV to renounce the treaty. In 1470 he restored his daughter Joanna's succession rights at Val de Lozoya, reigniting the succession dispute and contributing directly to the outbreak of the War of the Castilian Succession.
Political Outcome
Isabella recognized as heiress presumptive to Castile with title Princess of Asturias; Joanna removed from succession; civil war ended.
Henry IV's legitimacy contested; Joanna recognized as heir; kingdom divided by civil war
Henry IV's authority restored over all of Castile; Isabella designated heiress presumptive