Callistus I of Constantinople

Callistus I, known in Greek as Kallistos I, was Ecumenical Patriarch of Constantinople in the mid-fourteenth century, occupying the see from 1350 to 1353 and again from 1355 until his death in 1363. Almost nothing certain survives about his family, the year of his birth, or his native city; the record of his life begins with his monastic vocation. He became a monk on Mount Athos and a disciple of Saint Gregory of Sinai, the Sinai-trained teacher who in the early fourteenth century helped revive hesychast prayer on the Holy Mountain. Formed in that Athonite milieu, Callistus practiced the Jesus Prayer and inner watchfulness and later stood with the theological school associated with Gregory Palamas, which distinguished the unknowable divine essence from the uncreated energies in which human beings may participate. He remained a monk of the Eastern Church and is not recorded as having married or had children.

His standing as an Athonite elder and Palamite theologian led to his election as patriarch in 1350, during the reign of Emperor John VI Kantakouzenos, who favored the hesychast party after years of civil war and doctrinal conflict. In 1351 Callistus convened and presided over a synod in Constantinople, one of the so-called Palamite councils, which issued a tomos upholding Palamas’s teaching and condemning remaining anti-Palamite positions. That decision did much to fix hesychast theology as the official doctrine of the Byzantine Church. His first patriarchate ended in 1353 when he refused to crown Matthew Kantakouzenos, the emperor’s son, as co-emperor, on the ground that John V Palaiologos remained the legitimate sovereign. Deposed for that refusal, he withdrew from the capital; Philotheos Kokkinos was installed in his place and performed the coronation.

The political situation reversed soon afterward. John VI abdicated in 1354, John V Palaiologos recovered the throne, and in 1355 Callistus was restored as patriarch while Philotheos was removed. In this second tenure he governed a church strained by Ottoman advance in Asia Minor, Latin diplomatic pressure, and the aftermath of Byzantine civil conflict, while continuing to speak for Palamite Orthodoxy. He is credited with hagiographical and spiritual writing, above all a Life of Gregory of Sinai, an important source for the history of hesychasm. A well-known handbook of hesychast practice, the Century associated with the names Kallistos and Ignatius Xanthopoulos, has sometimes been linked to him, but modern scholarship often assigns that work to another Kallistos, and the identification with the patriarch remains uncertain.

A major external problem of his patriarchate was the breach with the Serbian Church. In 1346 Stefan Dušan had obtained the elevation of the Archbishop of Peć to patriarchal rank, a step Constantinople treated as uncanonical and which produced a schism. After Dušan’s death Callistus sought a settlement. In 1363 he traveled into Macedonian lands then under Serbian control, intending to negotiate with the Serbian court connected with Serres—then associated with the circle of Dušan’s widow—over ecclesiastical reunion and related matters. He died at Serres in 1363 before the embassy could be completed. The schism with Serbia was healed only later, in the 1370s, under a subsequent patriarch. Callistus is venerated as a saint in the Eastern Orthodox Church; a traditional commemoration falls on 20 June. The place of his burial is not firmly established in the sources, and no reliable evidence records a wife or children, which accords with his life as an Athonite monk and bishop of the Eastern Church.