In Africa the movements of Abd-al-Mumen, who had been the general of the Almohades and was now their sovereign, began to excite the alarm of Ali. The successor of the Mahdi began his reign with an expedition whose destructive course extended to the city of Morocco. Tashfin, the ablest of the Almoravide captains, was recalled from Spain; but, despite his reputation and the skilful disposition of his forces, the battalions of Ali, dominated by a craven and superstitious fear, instinctively recoiled from the presence of the enemy. All the experience and resolution of the youthful prince, who had redeemed the Moslem cause in the Peninsula, were insufficient to counteract the evil influence emanating from religious fraud, which, by the force of a distempered imagination, could transform a bold and courageous people into a race of poltroons and slaves. His continual reverses preyed upon the mind of Ali, and his moments were distracted by the signs of the imminent and apparently inevitable collapse of his power. The memory of his early grandeur offered a distressing contrast to the misfortunes of his declining years; and, overcome with mortification and sorrow, he passed from life, bequeathing to his son Tashfin a disheartened army, an exhausted treasury, and a royal inheritance of diminished jurisdiction and doubtful value. The ill-fortune of Tashfin followed him upon the throne. Defeated by Abd-al-Mumen, he collected all his resources for a supreme and final effort. Such of the Desert tribes as had held aloof from the Mahdi were enlisted. Every available soldier in Africa was called to arms. The garrisons of Andalusia were almost denuded of troops. With the Moorish squadrons of Spain came also a body of four thousand Mozarabes, who, accustomed to long service under Moslem standards, had almost forgotten their ancestry, their traditions, and their faith. These auxiliaries, amenable to discipline and experienced in border warfare, were far more formidable than their scanty numbers would denote. On the plains of Tlemcen the two armies whose valor was to decide the fate of an empire faced each other. The Almoravides far outnumbered their foes, but the mystic spell of superstition more than compensated for numerical superiority; the soldiers of Tashfin were terrified by imaginary apparitions and supernatural voices, and after a brief but sanguinary contest Abd-al-Mumen remained master of the field. Tashfin was soon afterwards killed in the vicinity of Oran by a fall from a precipice, and with his death vanished the last hope of the Almoravide monarchy.