Ibn Nasr, the founder of the Nasrid Dynasty, was forced to flee to Jaén to avoid persecution by King Ferdinand III of Castile and the Reconquista supporters working to end Spain's Moorish rule. After retreating to Granada, Ibn-Nasr took up residence at the Palace of Badis ben Habus in the Alhambra. A few months later, he embarked on the construction of a new Alhambra fit for the residence of a sultan. According to an Arab manuscript since published as the Anónimo de Granada y Copenhague,
This year, 1238 Abdallah ibn al-Ahmar climbed to the place called "the Alhambra" inspected it, laid out the foundations of a castle and left someone in charge of its construction...
The design included plans for six palaces, five of which were grouped in the northeast quadrant forming a royal quarter, two circuit towers, and numerous bathhouses. During the reign of the Nasrid Dynasty, the Alhambra was transformed into a palatine city, complete with an irrigation system composed of acequias for the gardens of the Generalife located outside the fortress. Previously, the old Alhambra structure had been dependent upon rainwater collected from a cistern and from what could be brought up from the Albaicín. The creation of the Sultan's Canal solidified the identity of the Alhambra as a palace-city rather than a defensive and ascetic structure.