[20] The turning point of their presence in the Iberian Peninsula came in 1212, when Muhammad al-Nasir (1199–1214) was defeated at the Battle of Las Navas de Tolosa in the Sierra Morena by an alliance of the Christian forces from Castile, Aragon and Navarre.

He also opposed their sponsorship of the Maliki school of jurisprudence, which drew upon consensus (ijma) and other sources beyond the Qur'an and Sunnah in their reasoning, an anathema to the stricter Zahirism favored by Ibn Tumart.

After being expelled from Bejaia, Ibn Tumart set up camp in Mellala, in the outskirts of the city, where he received his first disciples – notably, al-Bashir (who would become his chief strategist) and Abd al-Mu'min (a Zenata Berber of the Kumiya tribe who would later become his successor).

At length, towards the end of Ramadan in late 1121, after a particularly moving sermon, reviewing his failure to persuade the Almoravids to reform by argument, Ibn Tumart 'revealed' himself as the true Mahdi, a divinely guided judge and lawgiver, and was recognized as such by his audience.

On the advice of one of his followers, Omar Hintati, a prominent chieftain of the Hintata, Ibn Tumart abandoned his cave in 1122 and went up into the High Atlas, to organize the Almohad movement among the highland Masmuda tribes.

Their principal damage was in rendering insecure (or altogether impassable) the roads and mountain passes south of Marrakesh – threatening the route to all-important Sijilmassa, the gateway of the trans-Saharan trade.

[25] Ibn Tumart's closest companion and chief strategist, al-Bashir, took upon himself the role of "political commissar", enforcing doctrinal discipline among the Masmuda tribesmen, often with a heavy hand.

[27] Although a Zenata Berber from Tagra (Algeria),[28] and thus an alien among the Masmuda of southern Morocco, Abd al-Mu'min nonetheless saw off his principal rivals and hammered wavering tribes back to the fold.

He persuaded them by various means – including taking some families as hostages to Marrakesh and more generous actions like offering them material and land incentives – to move to present-day Morocco and join the Almohad armies.

[56] In 1212, the Almohad Caliph Muhammad 'al-Nasir' (1199–1214), the successor of al-Mansur, after an initially successful advance north, was defeated by an alliance of the three Christian kings of Castile, Aragón and Navarre at the Battle of Las Navas de Tolosa in the Sierra Morena.

The Almohads passed through a period of effective regency for the young caliph, with power exercised by an oligarchy of elder family members, palace bureaucrats and leading nobles.

The palace bureaucrats in Marrakesh, led by the wazir Uthman ibn Jam'i, quickly engineered the election of his elderly grand-uncle, Abd al-Wahid I 'al-Makhlu', as the new Almohad caliph.

His chief advisor, the shadowy Abu Zayd ibn Yujjan, tapped into his contacts in Marrakesh, and secured the deposition and assassination of Abd al-Wahid I, and the expulsion of the al-Jami'i clan.

Knowing they were outnumbered, the Almohad governors of the city refused to confront the Portuguese raiders, prompting the disgusted population of Seville to take matters into their own hands, raise a militia, and go out in the field by themselves.

Trust in the Almohad leadership was severely shaken by these events – the disasters were promptly blamed on the distractions of Caliph al-Adil and the incompetence and cowardice of his lieutenants, the successes credited to non-Almohad local leaders who rallied defenses.

He promptly purchased a truce from Ferdinand III in return for 300,000 maravedis, allowing him to organize and dispatch the greater part of the Almohad army in Spain across the straits in 1228 to confront Yahya.

Ibn Hud and the other local Andalusian strongmen were unable to stem the rising flood of Christian attacks, launched almost yearly by Sancho II of Portugal, Alfonso IX of León, Ferdinand III of Castile and James I of Aragon.

In their African holdings, the Almohads encouraged 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.

They sought to disseminate ibn Tumart's beliefs; he was the author of the Aʿazzu Mā Yuṭlab, the Counterpart of the Muwatta (محاذي الموطأ), and the Compendium of Sahih Muslim (تلخيص صحيح مسلم).

The abolishment of the dhimmi status of religious minorities further stifled the once flourishing Golden age of Jewish culture in Spain; Maimonides went east and many Jews moved to Castillian-controlled Toledo.

[62] The Almohad ideology preached by Ibn Tumart is described by Amira Bennison as a "sophisticated hybrid form of Islam that wove together strands from Hadith science, Zahiri and Shafi'i fiqh, Ghazalian social actions (hisba), and spiritual engagement with Shi'i notions of the imam and mahdi".

Although Ibn Rushd (who was also an Islamic judge) saw rationalism and philosophy as complementary to religion and revelation, his views failed to convince the traditional Maliki ulema, with whom the Almohads were already at odds.

[82] The Book of Knowledge of All Kingdoms, written by a Franciscan friar in the 14th century (well after the end of the Almohad period), describes the flag of Marrakesh as being red with a black-and-white checkerboard motif at its center.

However, it deviates in its depictions of the frontispiece, interior, and teaching scenes, which show similarities to scientific manuscripts from the central Islamic world, typically considered to have consisted of the Arabian peninsula, northeast modern Iran, and the Fertile Crescent.

[104][105] Jonathan Bloom cites the white and green glazed tiles on the minaret of the Kutubiyya Mosque, dating from the mid-12th century in the early Almohad period, as the earliest reliably-dated example of zellij in Morocco.

[108] The Kutubiyya Mosque's minaret in Marrakesh originally had polychrome painted decoration around the windows and blind arches on its exterior façades, featuring a mix of geometric and vegetal arabesque motifs.

[111] The decorations feature red ochre paintings of concave hexadecagons and eightfold rosettes on engraved white lime mortar in a pattern that fits the hammam's geometric skylight holes.

[133] The Alcázar Genil (originally called al-Qaṣr as-Sayyid) in Granada, created in the late Almohad period and later remodeled by the Nasrids, stood next to an enormous pool on the outskirts of the city.

María Rosa Menocal, a specialist in Iberian literature at Yale University, has argued that "tolerance was an inherent aspect of Andalusian society", and that the Jewish dhimmis living under the Caliphate, while allowed fewer rights than Muslims, were still better off than in Christian Europe.

[140] In 1198, the Almohad emir Abu Yusuf Yaqub al-Mansur decreed that Jews must wear a dark blue garb, with very large sleeves and a grotesquely oversized hat;[145] his son altered the colour to yellow, a change that may have influenced Catholic ordinances some time later.