A Berber Muslim empire that ruled parts of North Africa and al-Andalus.
The Almohad Caliphate (al-Muwahhidun, "the unitarians") rose from Ibn Tumart's Atlas-mountain reform movement — proclaiming himself Mahdi against Almoravid "anthropomorphism" — into the empire his lieutenant Abd al-Mumin built: Marrakesh taken (1147), the Maghreb united to Tunisia, and al-Andalus absorbed under caliphs who styled themselves successors to the Prophet outright.
Its century of power framed the western Mediterranean: Yaqub al-Mansur's victory at Alarcos (1195) the apogee, the philosophical court of Averroes its paradox — and the coalition defeat at the Battle of Las Navas de Tolosa (1212) the turning point after which the caliphate unravelled, its Iberian collapse opening the great Christian conquests of the thirteenth century.
Ibn Tumart returned from eastern study (c. 1117) preaching tawhid — God's absolute unity — against the Almoravid establishment's literalism and its jurists' power: moral censor, tribal organiser, and finally self-proclaimed Mahdi at Tinmal in the High Atlas (c. 1121), building among the Masmuda Berbers a hierarchical revolutionary community (the Ten, the Fifty, the tribal councils) with takfir's license against Muslim opponents.
His successor Abd al-Mumin — a Zanata outsider, organiser of genius — turned sect to empire in twenty years: the Atlas held, Tlemcen and Fez taken, Marrakesh stormed (1147) with the last Almoravids, then the eastward sweep to Ifriqiya (Tunis, Mahdia 1159–60) — the first unification of the whole Maghreb — and al-Andalus, invited by post-Almoravid taifa chaos, garrisoned and absorbed with Seville as the peninsular capital.
The great caliphs ruled a dual empire from Marrakesh and Seville: Abu Yaqub Yusuf and Yaqub al-Mansur patronising the age's philosophy (Averroes and Ibn Tufayl at court — the Commentator's Aristotle written under Almohad protection, his late disgrace a faction's victory) while prosecuting jihad — al-Mansur's Alarcos (1195) crushing Alfonso VIII of Castile and taking the "victorious" laqab home to build the Kutubiyya's sister minarets: Seville's Giralda, Rabat's unfinished Hassan.
The answer came as coalition: Innocent III's crusade-bull uniting Castile, Aragon, and Navarre (with the papacy holding Alfonso IX's feud in check), and at Las Navas de Tolosa (16 July 1212) the caliph al-Nasir's host was annihilated — the Navarrese cutting the chained guard of the caliphal tent, the banner sent to Rome. The empire's spine broke: al-Nasir dead within two years, child-caliphs and doctrinal repudiations (al-Mamun renouncing the Mahdi's creed, 1229) dissolving legitimacy while Marinids rose in Morocco, Hafsids in Tunisia, Zayyanids at Tlemcen — and in Iberia the "great conquests" harvested the wreck: Córdoba (1236), Valencia (1238), Seville (1248).
The Almohad state was ideology institutionalised: the Mahdi's infallible doctrine as constitution, a ruling hierarchy of the founding councils and the sayyids (Abd al-Mumin's house monopolising the caliphate), the talaba as doctrinal cadres-cum-inspectors, and the empire's startling innovation — a caliphate claimed in full, Friday prayers naming no Abbasid, coinage square-dirhamed and creed-stamped.
Administration ran on Berber tribal contingents and Andalusi bureaucrats, provincial sayyid-governors from the royal kin, a formidable navy (Mediterranean's strongest in al-Mansur's day), and fiscal rigour that funded monuments and armies alike; the doctrine's hard edge showed in the dhimma's effective abolition — forced conversions and the Jewish flight (Maimonides's family among the exiles) marking the founding decades, softening in practice as empire aged.
Ibn Tumart, the Mahdi, d. 1130 — the movement's founder-doctrine.
Abd al-Mumin, caliph 1130–1163 — Marrakesh, the Maghreb united, al-Andalus entered: the empire-builder.
Abu Yaqub Yusuf, 1163–1184 — the philosophers' patron; died besieging Santarém.
Yaqub al-Mansur, 1184–1199 — Alarcos's victor; the great minarets' builder.
Muhammad al-Nasir, 1199–1213 — Las Navas's loser; the unravelling's first caliph.
Almohadism was reform as state religion: creed-catechisms in Berber and Arabic, the Mahdi's writ over the jurists, purist mosque-building whose austerity became a style — the Kutubiyya, Tinmal's memorial mosque, the Giralda — and a censorious public piety that nonetheless sheltered the century's boldest falsafa: the Almohad paradox of Averroes writing the Decisive Treatise for a caliph while the talaba burned other books.
Its society moved armies and ideas across the strait both ways: Andalusi secretaries and poets in Marrakesh, Berber garrisons in Seville, the trans-Saharan gold trade funding the dinar's prestige — and its minorities' experience darkened the convivencia: the forced conversions' generation seeding both the Maghreb's Islamised Jewish communities and the exiles (Maimonides to Cairo) who carried Andalusi learning east.