The Almohad movement that took Marrakesh in 1147 and crossed into al-Andalus rejected the dhimma arrangement under which Jews and Christians had lived under Muslim rule, and required conversion to Islam. Jewish communities across the Maghrib and al-Andalus responded by outward conversion, by flight to the Christian kingdoms of northern Iberia, to Provence or to Egypt, or were destroyed; the Mozarabic Christian communities of al-Andalus, already reduced, effectively disappeared, with many deported to North Africa. Maimonides' family left Córdoba and eventually settled in Fustat, and his Epistle on Forced Conversion is addressed to Jews living outwardly as Muslims. The episode ended the long period in which al-Andalus sustained large protected non-Muslim communities. Numbers cannot be recovered; recent scholarship, including the Brill volume on forced conversion, has also debated how systematic and how sustained Almohad enforcement actually was, as against its representation in later Jewish memory.
The Almohad caliphate abolished dhimmi status across the Maghrib and al-Andalus, requiring conversion to Islam, and Jewish and Christian communities converted, fled or were destroyed
No defensible denominator exists. Twelfth-century al-Andalus and the Maghrib have no surviving population registers, and reconstructions of Andalusi Jewry rest on the Cairo Geniza correspondence, communal responsa and later expulsion-era data — sources that document communities without sizing them. Published estimates differ by an order of magnitude, and the Mozarab Christian population is even less well attested.
No usable figures. Hebrew sources record killings at particular places, notably in the initial Almohad advance across the Maghrib, but give no totals, and the dominant outcomes recorded are conversion and flight rather than mass killing.
The suppression of synagogues and churches and the abolition of protected status for Jews and Christians is documented in Jewish responsa and chronicles, in Maimonides' Epistle on Forced Conversion, and in the Brill scholarship cited.
Spain, Morocco, Egypt