Baptismal exorcism as proof of original sin: the legacy of Augustine’s liturgical argument in the Early Medieval West

In the wake of the Pelagian controversy, Augustine of Hippo repeatedly referred to liturgical practices as arguments to promote his views on original sin. A particularly prominent argument in his polemical writings, repeated with great insistence in his controversy against Julian of Eclanum, is that the rites of exorcising and blowing at infants at baptism would provide proof of the necessity of cleansing them from original sin. This paper traces the destiny of this argument after Augustine’s death. First, it demonstrates how it was soon reused by Prosper of Aquitaine in his Auctoritates de gratia Dei, which were later transmitted together with Celestine’s Letter 21, and borrowed and copied in a number of Western sources, in particular in the letter of the Deacon Peter and other Scythian monks to African bishops exiled in Cagliari in the early sixth century, in a late antique Latin pseudo-Chrysostom homily from the Morin collection and in Bede’s commentary on First Samuel. Second, it shows the use of Augustine’s argument in renewed debates against allegedly Pelagian views in the works of pope Gelasius I, and in a synthesis on the catechumenate written by the deacon John in a letter sent to the aristocrat Senarius. This article sheds light on Augustine’s legacy and the signifiance of his intermediary Prosper of Aquitaine, and leads us to reflect on the continuity of debates on infant baptism and original sin long after the official condemnation of Pelagianism.