Nikephoros Kallistos Xanthopoulos

[2] His most popular work, the voluminous Ecclesiastica historia, constitutes a significant documentary source on primitive Christianity and its doctrinal controversies, as well as for hagiographical, liturgical, and legendary texts from Byzantine culture.

[5] Xanthopoulos' 23-volume Ecclesiastica Historia (Greek: Εκκλησιαστική Ιστορία; "Church History"), of which only the first eighteen volumes survive, starts the historical narrative from the time of Christ and continues until the execution of the emperor Phokas in 610.

[4] The work includes descriptions of secular events, such as the accession of emperors and military campaigns, but emphasizes ecumenical councils, doctrinal disputes, and the four eastern patriarchates.

[6] Among the comments and notes that were added by Xanthopoulos, the book contains the phrase Κύριε βοήθει τῶ δούλω Νικοφόρω Καλλίστω ("Lord help your slave Nikephoros Kallistos"), which served as both a prayer and a signature.

[7] The work was dedicated to the emperor Andronicus II Palaeologus and it contributed to the monarch’s nationalist movement exalting Greek culture and Orthodoxy above Latin Christianity.