The letters by Athanasius I addressed to Emperor Andronicus II, to members of his family, and to imperial officials reveal much that is of interest in the political, social, and religious spheres of the Byzantine Empire just before and just after the turn of the thirteenth century.

The correspondence sheds light on the events of his two patriarchates (1289–1293, 1303–1309) and it corrects accounts found in the histories of Pachymeres and Gregoras. Political and social conditions of the empire are here described in detail as the patriarch struggled to alleviate the misery of the people and to discipline the officials of the Church for their venality and indolence. The letters also provide glimpses of daily life in Byzantium and discuss otherwise unknown personages.