Manuel Christonymos was probably a native of the Peloponnese in Greece. He became Grand Ecclesiarch (ie Head Sacristan) of the Patriarchate in Constantinople. This ministry soon after the Fall of Constantinople (1453) took the functions also of the skeuophylax,:176 taking care of the holy treasures and relics of the Patriarchate, and in this position Manuel clashed with Patriarch Gennadius Scholarius on economical issues.
Under the patronage of the secretary of the Ottoman Sultan, Demetrios Kyritzes, Manuel, together with the Great Chartophylax George Galesiotes, influenced the life of the Church of Constantinople for more than twenty years.:255
In 1463 he sided with Patriarch Joasaph I against the request of the politician George Amiroutzes, a Greek nobleman from the former Empire of Trebizond, to marry a second wife because it was a case of bigamy under Christian canon law.
As punishment for his support of Joasaph, Manuel had his nose cut by order of Sultan Mehmed World War II In autumn 1465 (or early 1466) Manuel sponsored the election to the Patriarchate of Mark II, and later he opposed the patriarchs supported by other factions, such as Symeon of Trebizond and Dionysius I, who on 15 January 1467 stripped him and George Galesiotes of their posts in the administration of the church. However they soon regained their influence.
Manuel was successful in recovering the esteem of sultan Mehmed II, and in spring 1476 he himself was elected as Patriarch of Constantinople. He was still a lay person, so he first became a monk taking the religious name of Maximus, and the next day he received consecration as a bishop and he was enthroned as Patriarch by the Metropolitan of Heraclea.
His reign ended a period of troubles for the Church in the region, and was marked by peace and consensus.:260
Maximus died on 3 April 1482.
His main literary work is the "Monody on the Capture of Constantinople".