Narratives of Authority around Chalcedon’s Canon 28: The Emperor Marcian, Bishop Leo I, and the Functions of Late-Antique Imperial Letters in Ecclesiastical Letter Collections

Abstract: In the context of fifth-century ecclesiastical disputes, more specifically during the aftermath of the Council of Chalcedon with its controversial canon 28, imperial communication to Christian clergy could not be as straightforward as usual. This article proposes that the diplomatic relationship between the Eastern Roman emperor Marcian (450–457 c.e.) and Bishop Leo I of Rome (440–461 c.e.) was governed by interdependence. Through examining the rhetoric of authority in Marcian’s understudied letter to Leo from December 18, 451, and placing it in the context of its transmission history in two antithetical late-antique letter collections, this article demonstrates how Marcian’s letter to Leo could be reused to defend consecutively both Rome and Constantinople thanks to its rhetorical subtletly. It argues that the divergent functions of Marcian’s letter in the fifth-century Greek Chalcedonian letter collection B and the ninth-century Latin Collectio Thessalonicensis were made possible by its diplomatic phrasing and the ambiguity of the Emperor’s position in theological disputes. Thus, it clarifies the functions of correspondence in ecclesiastical decision-making processes and adds to our understanding of textual and imperial authority in the Late Roman Empire.