Throughout the Moorish rule of Gibraltar, the town was used as a base for bandit raids into Castilian territory. In 1436, Enrique Pérez de Guzmán, 2nd Count de Niebla (grandson of Alonso Pérez de Guzmán, who captured Gibraltar after the first siege) assembled a force of five thousand men with which he intended to storm Gibraltar and dismantle the raiders’ base. He put his son, Juan Alonso de Guzmán, 1st Duke of Medina Sidonia in command of an army which marched from Tarifa to blockade the isthmus, while he led a fleet to land men on the beach.

When Enrique arrived, he found the town’s defences significantly stronger than he had anticipated – in particular, the sea wall had been extended since earlier sieges to prevent access to the Upper Rock from the beach. When his men landed, they found themselves caught between the tide and the sea wall, while the defending forces bombarded them with missiles. Enrique ordered his forces to withdraw, but was drowned when his boat capsized after several stranded men attempted to board it.

Lacking the funds for an extended siege, Juan marched his army away, while the Moors recovered his father’s body, decapitated it, and hung it in a basket above the town walls.

The Moors retained control of Gibraltar.