In Summer 407 AH/1016 AD, a a wave of mass violence targeting Isma’ili Shi’i Muslims swept across Ifriqiyah, a province of the Fatimid caliphate ruled by the Zirid dynasty. Following their move to Egypt in the late 4th/10th century, the Fatimid caliphs had appointed the Zirids, a dynasty of Sanhaja Berbers, as their governors and deputies in North Africa. Despite occasional outbreaks of violence, for much of the 10th century, there had been a delicate, albeit uneasy, coexistence between the various Muslim communities in Ifriqiyah (Isma’ili Shi’is, Hanafis, Malikis, and Ibadis). The pogrom of 407/1016 was therefore a cataclysmic event that undermined this heterogeneous society. The massacres, which began in Qayrawan and spread across Ifriqiyah between 407/1016 and 408/1017, claimed the lives and property of thousands of Isma’ili Shi’is, essentially ending the existence of Isma’ilism as a significant presence in Ifriqiyah, where it had thrived for over a century. This paper assesses all the available Arabic textual evidence for these events, including historical chronicles, poetry, biographical dictionaries and hagiographies, composed between the 5th/11th and 8th/14th centuries, much, if not most, never previously consulted for this topic. It demonstrates that the violence was underpinned by various social, political, economic and religious factors and was linked to the increasing sectarian tensions throughout the Fatimid caliphate during the reign of al-Hakim bi Amr-illah (r. 386/996–411/1021), whose social and religious policies alienated large numbers of his Sunni subjects. Moreover, the increasingly anti-Isma’ili theological discourse among many Sunni communities across the Islamic world, best exemplified by the theological manifesto issued by the Abbasid caliph al-Qadir (r. 381/991–422/1031) in Baghdad, played a role in legitimizing such anti-Isma’ili violence. The massacres in Zirid Ifriqiyah marked the beginning of the end of Fatimid rule in North Africa and was part of a broader development during the reign of Zirid emir al-Mu ‘izz ibn Badis (r. 407/1016–454/1062) that witnessed the emergence of the hegemony of the Maliki-Sunni school of thought in Ifriqiyah. Reinterpretation of the evidence available highlights the role of local Sunni leaders, including Mihriz b. Khalaf (d. 413/1022), while also examining the broader impact of the events of 407/1016 and 408/1017 upon Fatimid-Zirid relations during the 5th/11th century.