Patriarch Kallistos I

Kallistos I served as Patriarch of Constantinople twice — 1350 to 1353, then 1355 until his death in 1363. Before that he was a monk on Mount Athos and a direct disciple of Gregory of Sinai, the man who revived hesychasm when the living practice had nearly disappeared. The lineage matters: what Gregory received from Arsenios in Crete, what he transmitted to his disciples on Athos, found its way into the highest ecclesiastical office in the Eastern Christian world.

This is not incidental. The fact that a Patriarch of Constantinople was a practitioner of the hesychast prayer — a man who had received the transmission personally, who had sat with the Jesus Prayer in a cell on the Holy Mountain before he sat in the patriarchal throne — meant something for the tradition's legitimacy. Barlaam had tried to make hesychasm a marginal phenomenon, a suspect practice of uneducated monks. The Patriarch's biography was an answer.

Note: there are at least three different figures named Kallistos in the Philokalia. Kallistos I is the Patriarch. Kallistos Xanthopoulos — who later became Patriarch Kallistos II — co-authored the comprehensive Directions to Hesychasts with Ignatios Xanthopoulos. Kallistos Angelikoudis wrote dense theological texts on divine union. They are different people. The collection contains writings by all three.