Johannes Cantacuzenus, a Byzantine emperor and historian, born in Constantinople in the beginning of the 14th century. During the reign of Andronicus II. he was " great domestic," or first lord of the bedchamber. He was a relative of the imperial family, and his talents gained for him the confidence of the people. Andronicus and his grandson and legitimate successor, Andronicus III., were in constant dispute; and when in 1328 Andronicus III. ascended the throne, Cantacuzenus, who had sided with him, was called to the supreme administration of affairs, and was also made generalissimo of the Byzantine forces. The attacks of the Ottoman Turks gave Cantacuzenus an opportunity to display his military skill. He was unsuccessful against them, but rendered valuable service to the empire in reuniting to it Lesbos and AEtolia, and bringing to an end the piracies of the Genoese in the AEgean. The emperor, dying in 1341, left his son, John Pa-laeologus, nine years of age, to the guardianship of Cantacuzenus. He soon aroused the jealousies of the empress mother, Anne of Savoy, who declared him a traitor, and to save his life he assumed the purple at Adrianople in 1342. The civil war which resulted, and which lasted five years, was finally concluded by his admitting his ward Paleeologus as the colleague of the throne, and giving him his daughter in marriage.

But the jealousy of the empress mother raised a new sedition in 1353, which continued till Palseologus took Constantinople in 1355. A short time afterward Cantacuzenus abdicated, and retired to a monastery, where he assumed the name of Joasophas Christodolus, devoted himself to literature, and produced a history of his life and times from 1320 to 1360 (printed in Paris in 1645 in 3 vols, folio, in the collection of the Byzantine historians). He also wrote several theological works, among which is a defence of Christianity against Mohammedanism, which drew from Pope Gregory XI. a commendatory letter. The only part taken by Cantacuzenus in political affairs after his abdication, was his successful effort to dissuade his son Matthias from an armed attempt to secure the succession. Matthias abandoned the contest in 1357. Cantacuzenus ended his days in his monastic retirement, as did also his wife, Irene, who had retired to a convent under the name of Eugenia. It is not certain in what year he died; but several authorities give the date as 1411, which would have made him fully 100 years old.