In 1489, the Christian forces began a painfully long siege of Baza, the most important stronghold remaining to al-Zagal. Baza was highly defensible as it required the Christians to split their armies, and artillery was of little use against it. Supplying the army caused a huge budget shortfall for the Castilians. Occasional threats of deprivation of office were necessary to keep the army in the field, and Isabella came personally to the siege to help maintain the morale of both the nobles and the soldiers. After six months, al-Zagal surrendered, despite his garrison still being largely unharmed; he had become convinced that the Christians were serious about maintaining the siege as long as it would take, and further resistance was useless without the hope of relief, of which there was no sign. Baza was granted generous surrender terms, unlike Málaga.