Epistle of Pope Sixtus (Xistus) III to Proclus, archbishop of Constantinople

This work includes a translation from Latin of the epistle of Pope Sixtus (Xistus) III to Archbishop Proclus of Constantinople (437), as well as an introductory article and historical and philological commentaries. There is an information about the author and the addressee of the epistle at the beginning of the article; then its analysis is given. The epistle sheds light on the relationships between the Roman See and the See of Constantinople and the See of Thessalonica in the 430s, and also provides a better understanding of the role of the Vicariate of Thessalonica in its relationship with the Churches of Rome and Constantinople. The text was probably written as a reaction to the appeal of the Illyrian bishops to the see of Constantinople, bypassing Anastasius of Thessalonica. Turning to Proclus, Sixtus defends the jurisdictional rights of the Archbishop of Thessalonica as papal vicar in Illyricum. At the same time, Illyricum is considered by Sixtus as a region subordinate to the See of Thessalonica, as the Pope stated in his other letters. The work emphasizes the connection of the epistle with other letters of Pope Sixtus (among them Si quantum, Gratulari potius and Doctor gentium). Sixtus reminds Proclus about an incident with bishop Idduas of Smyrna as well as about his support for the judgment of the Primate of Constantinople. It seems that by this Sixtus hoped to induce Proclus to act similarly in such situations when the Illyrian bishops could turn to Constantinople looking for its support. Sixtus calls on Proclus to support Anastasius in his rights and not to accept the bishops of his region without official letters (formatae).