Gibraltar was the eastern rock that closed the Bay of Algeci- ras at the southern end of the Iberian Peninsula.
Its strategic importance in the long struggle for the control of the straits between Africa and Spain was not as great as that of Tarifa or Algeciras, but its conquest became an obsession for King Alfonso XI of Castile. This was because the place had been lost during his reign to the Marīnid forces of Abu’l-Hasan (1333) after over twenty years of Castilian rule, and also because its capture would deny landing bases in the Iberian Peninsula to African forces and isolate inland Marīnid settlements like Ronda.
The siege began in early July 1349. Alfonso XI had previously guaranteed enough funds for the campaign. The collection of the alcabala (a new sales tax) was prolonged; royal domains were sold, and contributions from the church were imposed, as in the case of the cathedral of Avila. The siege was cut short by Alfonso XI’s death on 27 March 1350; he was the only Western Christian monarch to die from the Black Death. The plague had entered the Christian camp, but the king disregarded his council’s advice to leave the place and soon became infected. The Marīnids controlled Gibraltar until 1375. Rodrigo Ponce de Leôn, son of the count of Arcos, conquered it in 1462, but the duke of Medina-Sido- nia took charge of the strongpoint immediately; later his successor had to give it to the Castilian Crown.