Callistus II of Constantinople

Callistus II of Constantinople (Xanthopoulos or Xanthopulus, Medieval Greek: Κάλλιστος Ξανθόπουλος; died after 1397) was a Byzantine Hesychast monk and spiritual writer who reigned as Ecumenical Patriarch of Constantinople in 1397. He was Patriarch through the reign of the Byzantine Emperor Manuel II Palaiologos, and through his short Patriarchal reign, Constantinople was under siege by the Ottoman Sultan Bayezid I. Within the Orthodox Church, his memory is celebrated on 22 November.^[1]

Saint Callistus II of Constantinople
Ecumenical Patriarch of Constantinople
Church	Church of Constantinople
In office	17 May 1397 – c. August 1397
Predecessor	Antony IV of Constantinople
Successor	Matthew I of Constantinople
Personal details
Died	After 1397
Denomination	Eastern Orthodoxy
Sainthood
Feast day	22 November

His surname indicates that he was from the monastery of Xanthopoulos. The majority of Patriarchs in the 14th century were monks in the Hesychast tradition.