In October 2019, I undertook a research visit at the Bibliothèque Nationale de France in Paris. There, I consulted several fourteenth-century codices transmitting the works of Philotheos Kokkinos, some of which bear his autograph interventions (e.g. Paris. gr. 1276), as well as other codices carrying the works of Gregory Palamas. Moreover, I made the autopsy of the fourteenth-century codex Paris. gr. 1276, which transmits the unedited letter to Petriotes, for which I will prepare a critical edition.