Analysing the cultural context in which the archbishops' chapel in Ravenna was built, the article proposes a new interpretation of the structure. Designed in a period when the Catholic Church and the Arian court were clashing, and displaying numerous baptismal motifs, the chapel seems to have been designed as a secluded baptistery. The structure's baptismal character transpires from its architecture and iconography, analysed here on the backdrop offered by Late Antique baptismal theory and iconography.