It is widely accepted that, while under Fatimid rule, the population of Egypt had remained Sunni. The Upper Egypt region, however, is a distinctive exception to this rule since Shi'ism (though not necessarily the Isma'ili brand) enjoyed growing popularity and—for a short period—even became the majority denomination in cities like Aswan. My paper (a) explores the influence that Fatimid governance had in shaping the cultural, religious and intellectual life of the region, and (b) appraises the reasons that caused Shi'ism to rise. From the reign of the imam-caliph al-Mustansir until the mid of the 12th century, Upper Egypt came to occupy a strategic role as the nerve centre of a flourishing international community of traders, scholars and pilgrims, following the Fatimids’ establishment of da‘wa, political and trading alliances with their Isma'ili vassals in Yemen, the Sulayhids. The favour that Shi‘ism enjoyed in Upper Egypt in the period under discussion was not due to doctrinal preferences among locals resulting from da‘wa activities but was rather established through the traffic of people who converged in the region for mundane/practical reasons. While Shi‘ism became the denomination of choice for trading and administrative purposes, it was the output of the Sunni community that continued to influence the cultural, religious and scholarly landscape. I draw from textual, documentary and material sources. My methodological approach is socio historical, blending elements of prosopographical and urban histories. Beside the most widely used primary sources such as, for example, the works of al-Maqrizi, I base my research on biographical dictionaries. Particularly relevant is al-Udfuwi’s al-Tali‘ al-sa‘id which is dedicated to the leading figures in Upper Egypt in the pre-modern period. The social history of Upper Egypt under the Fatimids has remained so far understudied; my contribution builds on the limited existing research produced from varied perspectives, including contributions by J-C. Garçin (urban history), J.M. Bloom (architecture) and D. J. Stewart (socio-linguistics).