In August 1462, an inhabitant of then-Muslim Gibraltar defected to Tarifa, where he converted to Christianity. He informed the Governor of Tarifa, Alonso de Arcos that Gibraltar was largely undefended. A sceptical Alonso took a relatively small force to Gibraltar to attempt to verify the defector’s claims.
Upon arrival, Alonso’s men took up concealed positions from which they could observe the town. They captured a Moorish patrol and tortured them for information, which confirmed the defector’s claims. Lacking sufficient men to hold the town even if he managed to capture it, Alonso sent for reinforcements from nearby Christian towns and from Juan Alonso de Guzmán, 1st Duke of Medina Sidonia (who blockaded the isthmus in the seventh siege and whose father’s body still hung above the town walls).
After contingents arrived from local towns, Alonso launched an assault, which resulted in two days of heavy fighting, after which the Moors sent an emissary to offer terms for surrender. However, Alonso did not have the authority to accept the surrender, and had to await the arrival of a more senior noble. A contingent from Arcos stormed the town after the Jerez contingent attempted to accept the Moors’ surrender, prompting the town’s inhabitants to retreat inside the castle walls.
With Gibraltar in Christian hands, a dispute broke out between the de Guzmáns and the Ponce de Leons over which family’s standard would be raised above the castle. The Ponce de Leons’ men withdrew when they believed the de Guzmáns had set a trap for them, leaving the Rock under the control of the de Guzmáns and the two families mortal enemies.
Gibraltar was under the control of the De Guzmán family.