Manichaeism was a radically different form of Christianity that developed in the Persian Empire of the Sassanids in the third century A.D. It was characterised by the teachings of the self-declared Apostle of Jesus Christ, Mani; and by an engagement with the religions of Iran and India such as Zoroastrianism and Buddhism. When the missionaries of this church reached the Roman Empire from the 260s on there ensued a furious debate over the true meaning of the Gospel, a conflict ultimately won by what we now think of as the normative Christian tradition. But Manichaean achieved considerable successes, especially in Asia where it ultimately spread to South China; whilst Augustine of Hippo was its most famous convert in North Africa. The textual finds at ancient Kellis (Ismant el-Kharab) have recovered unique texts on papyrus and wooden board codices belonging to the Manichaean expansion into Egypt through the fourth century. Indeed, they include unparalleled personal documents belonging to Manichaean lay believers living and working in the Oasis and the Nile Valley, and thus a first ever opportunity to study the social and economic context for this clash of Christian churches as it was played out in the provincial society of Late Antiquity.