Baptism for the early Christians was a subject of crucial importance, and its symbolism fired the imagination of writers throughout the Christian world. Arator, the Roman sub-deacon who wrote a verse-commentary on the Acts of the Apostles in A.D. 544, was no exception. The Historia Apostolica is a work of historical importance. Written at a time of crisis, politically and theologically, it is of interest as propaganda for a papacy under threat from Constantinople. But Arator's concentration on baptismal themes offers vital evidence of the transmission of exegetical ideas in late antiquity....