Optatus, bishop of Milevis (d. c. 390 CE), was a North African bishop and apologist for the Caecilianist (Caecilian) faction of the African church during the 4th-century CE schism. His treatise On the Donatist Schism provides the earliest history of the controversy. The work also reflects important developments in the western understanding of ecclesiology, the sacraments, Petrine priority, and the relations of the …