Johannes, emperor of the East, celebrated as a statesman, general, and historian, was born at Constantinople, of an ancient and opulent family; and, under the reign of the elder Andronicus, he held the high office of Great Domestic. In the disputes that ensued between that emperor and his grandson, Cantacuzenus espoused the cause of the latter; and when Andronicus II., on the abdication of his grandfather, ascended the throne (A.D. 1328), this able minister was intrusted with the supreme administration of affairs, in which capacity he displayed extraordinary vigour and ability. On the death of the emperor in 1341, Cantacuzenus was left regent, and guardian of his son John Palaeologus, who was but nine years of age. This trust he continued to discharge with fidelity, till the intrigues of the empress-mother and her faction rendered Cantacuzenus alarmed for his personal safety. Declared a traitor, he had but one resource; and accordingly he assumed the imperial purple in the autumn of 1321. A civil war ensued, which lasted six years, when he admitted John Palaeologus as his colleague in the empire; and this union was confirmed by the marriage of Palaeologus with the daughter of Cantacuzenus. Suspicions and enmities, however, soon arising, the war broke out again, and continued till John took Constantinople in 1355. A few days after, Cantacuzenus, unwilling to continue the effusion of blood, abdicated his share of the empire, and retired to a monastery, where he assumed the habit of a monk, under the title of Joasophas Christodulus. His wife also retired to a nunnery, and changed her name of Irene for that of Eugenia. In this retirement he lived till 1411, when he must have been upwards of a hundred years of age. Here he wrote a history of his own life and times, which has been incorporated in the series of the Byzantine historians; and also an apology for the Christian religion against that of Mohammed, under the name of Christodulus.