As a youth he performed the pilgrimage to Makkah, whence he was expelled on account of his severe strictures on the laxity of others, and thence wandered to Bagdad, where he attached himself to the school of the orthodox doctor al Ashari. But he made a system of his own by combining the teaching of his master with parts of the doctrines of others, and with mysticism imbibed from the great teacher Ghazali. His main principle was a rigid unitarianism which denied the independent existence of the attributes of God, as being incompatible with his unity, and therefore a polytheistic idea. Muhammad in fact represented a revolt against the anthropomorphism of commonplace Muslim orthodoxy, but he was a rigid predestinarian and a strict observer of the law. After his return to Morocco at the age of twenty-eight, he began preaching and agitating, heading riotous attacks on wine-shops and on other manifestations of laxity. He even went so far as to assault the sister of the Murabti (Almoravide) amir `Ali III, in the streets of Fez, because she was going about unveiled after the manner of Berber women. `Ali, who was very deferential to any exhibition of piety, allowed him to escape unpunished.
Ibn Tumart, who had been driven from several other towns for exhibitions of reforming zeal, now took refuge among his own people, the Masmuda, in the Atlas. It is highly probable that his influence would not have outlived him, if he had not found a lieutenant in 'Abd-el-Mumin el Kumi, another Berber, from Algeria, who was undoubtedly a soldier and statesman of a high order. When Ibn Tumart died in 1128 at the monastery or ribat which he had founded in the Atlas at Tinmal, after suffering a severe defeat by the Murabtis, 'Abd-el-Mumin kept his death secret for two years, till his own influence was established. He then came forward as the lieutenant of the Mahdi Ibn Tumart. Between 1130 and his death in 1163, 'Abd-el-Mumin not only rooted out the Murabtis, but extended his power over all northern Africa as far as Egypt, becoming amir of Morocco in 1149. Muslim Spain followed the fate of Africa, and in 1170 the Muwahhadis transferred their capital to Seville, a step followed by the founding of the great mosque, now superseded by the cathedral, the tower of which they erected in 1184 to mark the accession of Ya`kub el Mansur. From the time of Yusef II, however, they governed their co-religionists in Spain and Central North Africa through lieutenants, their dominions outside Morocco being treated as provinces. When their amirs crossed the Straits it was to lead a jihad against the Christians and to return to their capital, Marrakesh.
The Muwahhadi princes had a longer and a more distinguished career than the Murabtis (or Almoravides). Yusef II. or "Abu Ya`kub" (1163-1184), and Ya`kub I. or "Al Mansur" (1184-1199), the successors of Abd-el-Mumin, were both able men. They were fanatical, and their tyranny drove numbers of their Jewish and Christian subjects to take refuge in the growing Christian states of Portugal, Castile and Aragon. But in the end they became less fanatical than the Murabtis, and Ya`kub al Mansur was a highly accomplished man, who wrote a good Arabic style and who protected the philosopher Averroes. His title of Al Mansur, "The Victorious," was earned by the defeat he inflicted on Alfonso VIII of Castile at Alarcos in 1195. But the Christian states in Spain were becoming too well organized to be overrun by the Muslims, and the Muwahhadis made no permanent advance against them. In 1212 Mahommed III, "En-Nasir" (1199-1214), the successor of al Mansur, was utterly defeated by the allied five Christian princes of Spain, Navarre and Portugal, at the Battle of Las Navas de Tolosa in the Sierra Morena. All the Moorish dominions in Spain were lost in the next few years, partly by the Christian conquest of Andalusia, and partly by the revolt of the Muslims of Granada, who put themselves under the protection of the Christian kings and became their vassals.
The fanaticism of the Muwahhadis did not prevent them from encouraging the establishment of Christians even in Fez, and after the battle of Las Navas de Tolosa they occasionally entered into alliances with the kings of Castile. In Africa they were successful in expelling the garrisons placed in some of the coast towns by the Norman kings of Sicily. The history of their decline differs from that of the Murabtis, whom they had displaced. They were not assailed by a great religious movement, but destroyed piecemeal by the revolt of tribes and districts. Their most effective enemies were the Beni Marin ("Merinides") who founded the next Moroccan dynasty, the sixth. The last representative of the line, Idris IV., "El Wathik"' was reduced to the possession of Marrakesh, where he was murdered by a slave in 1269.
Muwahhadi (Almohad) Caliphs, 1145-1269