From the ruined building one gains, perhaps, the most satisfactory view of the Alhambra, as its reddish line of half-demolished walls is traced along the undulations of the mountain on which it stands; while the white ridges of the Sierra Nevada furnish a magnificent background for the picture, and set off the heavy mass of the unfinished palace of Charles the Fifth. Two centuries of prosperity, with a powerful Christian State almost at bow-shot, were as much as the Moors had any right to expect; and towards the third quarter of the fifteenth century there were signs that their knell was about to sound. The union of Aragon with Castile by the marriage of Ferdinand and Isabella was the note of doom. Two such sovereigns could not long leave the Moors undisturbed in their corner of the peninsula. Muley Aly, generally known by his surname, Abu-l-Hasan (which the Spaniards change into Alboacen, and many English writers into Aben Hasan), who was of a fiery and warlike nature, resolved to be beforehand with their Catholic majesties in opening the game of war. He refused to pay the customary tribute, and when the ambassador of Ferdinand came to insist, he made answer: "Tell your sovereigns that the kings of Granada who paid tribute are dead: our mint now coins nothing but sword-blades!" To make his meaning unmistakable, he proceeded to carry a raid into the lands of the Christians. Zahara was the spot he selected for attack. A gifted American author has told the story of the last wars of the Moors in his own eloquent style; and we must follow Washington Irving in relating the assault of Zahara.[27] [Illustration: PLAN OF THE ALHAMBRA]