Résumé :
The present study offers a new critical edition of fifteen letters of the bishop of Tabrīz Gregory Chioniades (fl. ca. 1300) and of one further anonymous letter, all preserved in the manuscript Vind. theol. gr. 203, as well as the first edition of yet another letter penned by Chioniades and preserved in the manuscript New York, Columbia University, Smith Western, Add. 10. An attempt at the reconstruction of Chioniades’ career is made, and the content of his letters is analysed, especially with a view to exploring the cultural and political history of the Empire of Trebizond. Codex Vind. hist. gr. 4, the archetype of the medieval tradition of Arrianos’ Anabasis and Indike and one of the most important Greek manuscripts held by the Austrian National Library (ÖNB), is shown to have belonged to Gregory Chioniades and to have passed through the hands of several owners in Trebizond before reaching Constantinople via Demetrios Angelos, a physician and copyist active in the Ottoman capital shortly after the Turkish conquest.