Isabelline Counteroffensive: The Fall of Trujillo and the Securing of Strategic Castilian Lands (Late 1475–1476)

As the War of the Castilian Succession (1475–1479) progressed, Isabella I of Castile and her supporters launched a major counteroffensive, seizing key territories that had previously backed Joanna la Beltraneja and her Portuguese allies.

The Capture of Trujillo and the Securing of Military Orders’ Lands

• In late 1475–early 1476, Isabelline forces launched a successful campaign against Portuguese and pro-Joanna positions.
• Trujillo, a vital city in Extremadura, was captured by Isabella’s supporters, cutting off Portuguese access to central Castile.
• Isabella’s forces also gained control of key military order territories, which had previously supported Joanna:
  • A significant portion of the Order of Calatrava's lands—weakening a major ally of Joanna.
  • The lands of the Order of Alcántara, further eroding Portuguese influence in Castile.
• Additionally, Isabella’s supporters secured the Marquisate of Villena, a large and strategically important domain in eastern Castile, further tilting the war in her favor.

Impact on the War

1. Weakened Joanna’s Support Base – With the loss of Trujillo and military order lands, Joanna and Afonso V were left with fewer Castilian allies.
2. Strengthened Isabella’s Position – Gaining control over the orders of Calatrava and Alcántara reinforced Isabella’s claim to the throne, as these orders had substantial military and political power.
3. Strategic Blow to Portugal – Afonso V’s forces were now increasingly isolated, with dwindling options for maneuvering in Castile.

A Turning Point Leading to the Battle of Toro (1476)

• The fall of Trujillo and other territories weakened the Portuguese position in Castile, setting the stage for the decisive Battle of Toro (March 1, 1476).
• Though the battle itself was militarily indecisive, Isabella’s political advantage grew, leading to the eventual collapse of the Portuguese campaign and the signing of the Treaty of Alcáçovas (1479).

The Isabelline counteroffensive, particularly the capture of Trujillo and control over military orders’ lands, was a turning point in the war, accelerating Joanna’s decline and Isabella’s final victory.