power of a new and growing political organization urgently demanded a settled habitation and a recognized centre of authority. Among the lofty crags of a mountain spur extending from the range of Tlemcen to the Atlantic stood the village of Tinamal. Its retired situation, its natural defences, its proximity to both the rich cities of the coast and the fertile regions of the interior, the character of its people, who were to a man ardent believers in the mission of the Mahdi, made it an admirable point either for the inauguration of a conquest or the institution of an harassing system of predatory warfare. It was approached by narrow and tortuous paths which, winding along the mountain side, disclosed, on the one hand, an inaccessible cliff, on the other, an abyss whose depths were shrouded in perpetual gloom. From its battlements, almost hidden in the clouds, the progress of a hostile party could be watched for miles as, with slow and uncertain steps, it pursued its hazardous way. In this mountain fastness the Mahdi fixed his residence and established his capital. The natural impediments in the path of an invader were greatly multiplied by the artificial resources of engineering skill. Towers and fortresses were raised at points commanding the various approaches to the mountain stronghold. Drawbridges were thrown across roaring torrents. Walls and gateways obstructed the passage, where an insignificant force might with ease check the progress of a numerous army. The village of Tinamal soon became a city, whose inhabitants, subsisting by the plunder of their neighbors, became the scourge and the terror of the peaceable and defenceless subjects of Ali. After a long sojourn in his seat of power, the Mahdi, about to succumb to a fatal disease, determined to signalize his closing days by an enterprise worthy of the pretensions he had assumed and of the success which had hitherto favored his undertakings. An army of forty thousand men was assembled for the capture of Morocco. In a desperate conflict under the walls of that city, the Almoravides, who outnumbered their opponents two to one, were put to flight and pursued with terrible carnage to its gates. But the fortunes of the Almohades, heretofore invincible, were now destined to receive a serious blow. Unaccustomed to the conduct of a siege, the soldiers of Abd-al-Mumen habitually neglected the precautions which, in the presence of an enemy, are indispensable to the security of a camp. Within the immense circuit of the capital were marshalled for a final struggle the collected resources of the empire. Thousands of fugitives from the recent disastrous battle had found an asylum behind its walls. Reinforcements had been drawn from every African province as well as from the diminished Andalusian armies, their own strength already sorely taxed by repeated incursions of the Christian foe. The constructing and handling of military engines were confided to a body