<P> 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 . </P> <P> With the fall of Baza and the capture of al - Zagal in 1490, it seemed as if the war was over; Ferdinand and Isabella believed this was the case . However, Boabdil was unhappy with the rewards for his alliance with Ferdinand and Isabella, possibly because lands that had been promised to him were being administered by Castile . He broke off his vassalage and rebelled against the Catholic Monarchs, despite holding only the city of Granada and the Alpujarras Mountains . It was clear that such a position was untenable in the long term, so Boabdil sent out desperate requests for external aid . The Sultan of Egypt mildly rebuked Ferdinand for the Granada War, but the Mamluks that ruled Egypt were in a near constant war with the Ottoman Turks . As Castile and Aragon were fellow enemies of the Turks, the Sultan had no desire to break their alliance against the Turks . Boabdil also requested aid from the Kingdom of Fez (modern Morocco), but no reply is recorded by history . North Africa continued to sell Castile wheat throughout the war and valued maintaining good trade relations . In any case, the Granadans no longer controlled any coastline from where to receive overseas aid . No help would be forthcoming for Granada . </P> <P> An eight - month siege of Granada began in April 1491 . The situation for the defenders grew progressively dire, as their forces for interfering with the siege dwindled and advisers schemed against each other . Bribery of important officials was rampant, and at least one of the chief advisers to Boabdil seems to have been working for Castile the entire time . After the Battle of Granada a provisional surrender, the Treaty of Granada, was signed on November 25, 1491, which granted two months to the city . The reason for the long delay was not so much intransigence on either side, but rather the inability of the Granadan government to coordinate amongst itself in the midst of the disorder and tumult that gripped the city . After the terms, which proved rather generous to the Muslims, were negotiated, the city capitulated on January 2, 1492 . The besieging Christians sneaked troops into the Alhambra that day in case resistance materialized, which it did not . Granada's resistance had come to its end . </P> <P> The most notable facet of the Granada War was the power of bombards and cannons to greatly shorten the many sieges of the war . The Castilians and Aragonese started the war with only a few artillery pieces, but Ferdinand had access to French and Burgundian experts from his recent wars, and the Christians aggressively increased their artillery forces . The Muslims, however, lagged far behind in their use of artillery, generally only using the occasional captured Christian piece . The historian Weston F. Cook Jr. wrote "Gunpowder firepower and artillery siege operations won the Granadan war, and other factors in the Spanish victory were actually secondary and derivative ." By 1495, Castile and Aragon controlled 179 pieces of artillery total, a vast increase from the paltry numbers seen in the War of the Castilian Succession . </P>

When did christian forces finally retake the kingdom of granada