Gregoras, Nicephorus(nīsĕf`ərəs grĕg`ərəs), c.1295–c.1359, Byzantine historian and theologian, one of the most learned men of his time. Among his scientific and philosophical works is a plan for a calendar reform similar to that effected by Pope Gregory XIII two centuries later. His chief book is the Roman History, covering the period from 1204 to 1359. This and the Histories of John Cantacuzene (see John VIJohn VI
(John Cantacuzene) , c.1292–1383, Byzantine emperor (1347–54). He was chief minister under Andronicus III, after whose death he proclaimed himself emperor and made war on the rightful heir, John V. He was aided by the Ottoman Turks.
..... Click the link for more information. , Byzantine emperor) are the primary sources for 14th-century Byzantine history. The two works complement each other. A staunch adherent of Byzantine Emperor Andronicus II, Gregoras temporarily fell out of favor with his successor and grandson, Andronicus III. Later, however, Gregoras was appointed (1333) to conduct the negotiations for the union of the Greek and Roman churches proposed by Pope John XXII. Gregoras was by then a famous man, but after he opposed doctrines that were approved (1351) by the Greek church, he was discredited and confined to a monastery until 1355.