Nicephorus Callistus Xanthopoulos, of Constantinople, the last of the Greek ecclesiastical historians, flourished around 1320.

His Historia Ecclesiastica, in eighteen books, brings the narrative down to 610; for the first four centuries the author is largely dependent on his predecessors, Eusebius, Socrates Scholasticus, Sozomen, Theodoret and Evagrius, his additions showing very little critical faculty; for the later period his labours, based on documents now no longer extant, to which he had free access, though he used them also with small discrimination, are much more valuable.

A table of contents of another five books, continuing the history to the death of Leo the Philosopher in 911, also exists, but whether the books were ever actually written is doubtful. Some modern scholars are of opinion that Nicephorus appropriated and passed off as his own the work of an unknown author of the 10th century. The plan of the work is good and, in spite of its fables and superstitious absurdities, contains important facts which would otherwise have been unknown. The history of Roman Catholicism receives little attention.

Only one manuscript of the history is known; it was stolen by a Turkish soldier from the library at Buda during the reign of Matthias Corvinus of Hungary and taken to Constantinople, where it was bought by a Christian and eventually reached the imperial library at Vienna.

Nicephorus was also the author of lists of the emperors and patriarchs of Constantinople, of a poem on the capture of Jerusalem, and of a synopsis of the Scriptures, all in iambics; and of commentaries on liturgical poems.