 The new sultan declared "jihad" against the Christian rulers of the Iberian Peninsula in 1315 and moved to establish a siege against Gibraltar.While Ismail's forces were digging in around Gibraltar, Castillian forces under the Prince Regent Peter of Castile – who exercised authority in the name of the infant king Alfonso XI of Castile – undertook a raid deep into Granada to plunder and destroy the emirate's rich agricultural lands.When news of the siege reached Peter at Cordoba, he left his army where it was and went to Seville to organise naval and land forces to lift the Nasrid blockade.