Two pieces of imperial correspondence from The Collectio Thessalonicensis: issues of their authenticity and contents

Introduction. The Collectio Thessalonicensis is a collection of documents compiled in the 9th century, in which, in addition to papal letters to the bishops of Illyricum and to the Patriarchs of Constantinople, Proclus and Anatolius, two lengthy fragments have been preserved, representing a letter from the Western Emperor Honorius (395-423) to the Eastern Emperor Theodosius II (408-450) and the latter's response. The correspondence apparently took place in 422 and is devoted to the privileges of the Roman see in Eastern Illyricum, which shortly before had become a prefecture of the Eastern Roman Empire with its capital at Thessalonica. The authenticity of these letters has long been rejected in the scholarly literature. As a consequence, the task of the article is to present the arguments of the old literature, provide new evidence of the authenticity of both fragments, and highlight the ecclesiastical-political and ecclesiastical-administrative situation that they reflect. Analysis. The arguments of J. Friedrich, Th. Mommsen, and E. Chrysos in favour of the forgery of these fragments are considered. These arguments range from complete denial to partial acceptance of their authenticity, with speculation about the motives for the falsification and the timing of its implementation. The author of the article points out the inconsistency of these arguments. The newest casual arguments of P. Riedlberger, which deny their authenticity, are also refuted. Based on ascertaining the authenticity of these documents, the author reconstructs the circumstances of the correspondence between the two emperors and the motives of both correspondents in recognising the authority of the Roman see in Eastern Illyricum. The text of the messages and their connections with other similar imperial documents are analysed, and the factor of influence on their composition of the ecclesiastical circles of the West and the East is determined.