Church and State in the Dispute over the Vicariate of Thessaloniki during the Pontificate of Boniface I

Abstract Following the appointment of Perigenes as bishop of Corinth in 419, some Illyrian bishops, upset that this violated the Nicene canon against the translation of bishops and that Boniface I, bishop of Rome from 418 to 422, had supported Perigenes’s election, secured a law from the eastern emperor, Theodosius II, that judicial appeals were to be heard at Constantinople (Cod. theod. 16.2.45). The innovation that Theodosius condemned was undoubtedly the practice of Illyrian bishops appealing through the bishop of Thessaloniki to Rome, a system that had flourished under several of Boniface’s predecessors, as documented in the letters of the Collectio Thessalonicensis. Boniface’s response was to enlist the support of Honorius, the western emperor, to appeal to his imperial nephew to reverse this decision as itself being an innovation (Boniface I, Ep. 10). Theodosius agreed (Boniface I, Ep. 11). This article examines the letters concerned in the light of the history of the vicariate of Thessaloniki and Boniface’s own relationship with imperial authority, which is demonstrated in the ultimately definitive involvement of Ravenna in settling the electoral controversy that surrounded Boniface’s own election in Rome. It argues that the whole Perigenes affair was one of the first examples of what has come to be called papal primacy, in that it was an exercise of ecclesiastical authority over an area that no longer belonged to his supervision, that Honorius complied with Roman episcopal wishes, and that Roman success was dependent upon the personal relationship between imperial uncle and nephew.