Like the Almoravids, the Almohads found their initial inspiration in Islamic reform. Their spiritual leader, the Moroccan Muhammad ibn Abdallah ibn Tumart, sought to reform Almoravid decadence. Rejected in Marrakech and other cities, he turned to his Masmuda tribe in the Atlas Mountains for support. Because of their emphasis on the unity of God, his followers were known as Al Muwahhidun (unitarians, or Almohads).

Although declaring himself mahdi, imam, and masum (infallible leader sent by God), Muhammad ibn Abdallah ibn Tumart consulted with a council of ten of his oldest disciples. Influenced by the Berber tradition of representative government, he later added an assembly composed of fifty leaders from various tribes. The Almohad rebellion began in 1125 with attacks on Moroccan cities, including Sus and Marrakech.

Upon Muhammad ibn Abdallah ibn Tumart's death in 1130, his successor Abd al Mumin took the title of caliph and placed members of his own family in power, converting the system into a traditional monarchy. The Almohads entered Spain at the invitation of the Andalusian amirs, who had risen against the Almoravids there. Abd al Mumin forced the submission of the amirs and reestablished the caliphate of Córdoba, giving the Almohad sultan supreme religious as well as political authority within his domains. The Almohads took control of Morocco in 1146, captured Algiers around 1151, and by 1160 had completed the conquest of the central Maghrib and advanced to Tripolitania. Nonetheless, pockets of Almoravid resistance continued to hold out in the Kabylie for at least fifty years.

After Abd al Mumin's death in 1163, his son Abu Yaqub Yusuf (r. 1163-84) and grandson Yaqub al Mansur (r. 1184-99) presided over the zenith of Almohad power. For the first time, the Maghrib was united under a local regime, and although the empire was troubled by conflict on its fringes, handcrafts and agriculture flourished at its center and an efficient bureaucracy filled the tax coffers. In 1229 the Almohad court renounced the teachings of Muhammad ibn Tumart, opting instead for greater tolerance and a return to the Maliki (see Glossary) school of law. As evidence of this change, the Almohads hosted two of the greatest thinkers of Andalus: Abu Bakr ibn Tufayl and Ibn Rushd (Averroes).

The Almohads shared the crusading instincts of their Castilian adversaries, but the continuing wars in Spain overtaxed their resources. In the Maghrib, the Almohad position was compromised by factional strife and was challenged by a renewal of tribal warfare. The Bani Merin (Zenata Berbers) took advantage of declining Almohad power to establish a tribal state in Morocco, initiating nearly sixty years of warfare there that concluded with their capture of Marrakech, the last Almohad stronghold, in 1271. Despite repeated efforts to subjugate the central Maghrib, however, the Merinids were never able to restore the frontiers of the Almohad Empire.

Data as of December 1993