It originated with Ibn Tumart, a member of the Masmuda, a Berber tribe of the Atlas Mountains. Ibn Tumart was the son of a lamplighter in a mosque and had been noted for his piety from his youth; he was small, ugly, and misshapen and lived the life of a devotee-beggar. As a youth he performed the pilgrimage to Mecca (or "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-Ash'ari. 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. Ibn Tumart in fact represented a revolt against what he perceived as Anthropomorphism in the 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 Almoravid (Murabit) 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 al-Mu'min al-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 Almoravids, Abd al-Mu'min 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 Murabits, 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 Muwahhids 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 Abu Yusuf Ya'qub al-Mansur. From the time of Yusuf 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 Muwahhid princes had a longer and a more distinguished career than the Murabits (or Almoravids). Yusuf II or "Abu Ya'qub" (1163-1184), and Ya'qub I or "al-Mansur" (1184-1199), the successors of Abd al-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 Murabits, and Ya'qub 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 in Battle of Alarcos (1195). But the Christian states in Spain were becoming too well organized to be overrun by the Muslims, and the Muwahhids made no permanent advance against them. In 1212 Muhammad III, 'al-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 Muwahhids 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 Murabits, 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 (Marinids) who founded the next Moroccan dynasty, the sixth. The last representative of the line, Idris II, "El Wathiq"' was reduced to the possession of Marrakesh, where he was murdered by a slave in 1269.