a Roman historian of the fourth century, was a native of Greece, born in the city of Antioch. Having served several years in the early part of his life in the army, he was afterwards promoted to the honourable station of protector domesticus. In the year 350 he entered the service of Constantius, the emperor of the east, and, under the command of Ursicinus, a general of the horse, he served during several expeditions. According to his own modest relation, it appears that he acquired considerable military fame, and that he deserved well of his sovereign. He attended the emperor Julian in his expedition into Persia, but history is silent whether or not he rose to any higher military rank than that which has already been mentioned. He was either in the city or the vicinity of Antioch when the conspiracy of Theodorus was discovered, under the reign of Valens, and was an eye-witness of the severe torments to which many persons were exposed by the emperor on that account.

But his lasting reputation was not to be acquired from military exertions. He left the army, and retired to Rome, where he employed his time and talents in writing the history of that empire during the period of three centuries. Though a native of Greece, he wrote in the Latin language; but, according to the remark of Velleius, his Latin shows that he was a Greek, and also a soldier. His history begins with the reign of Nerva, and continues to the death of Valens; and the work was originally divided into 31 books. Of these the first 13 have perished, and the 18 which remain commence with the 17th year of the reign of Constantius, and terminate at the year 375. But there are several facts mentioned in the history which prove that the author was alive in the year 392. Of this number are the accession of Theodosius to the eastern empire, the character of Gratian, and the consulate of Neotherius. Similar to the manner in which Herodotus, the father of Grecian history, read his history, Marcellinus read his books in public with general approbation. Some have reckoned the style harsh and redundant, but this may easily be excused, from his education and military life; and the valuable information communicated abundantly compensates for that defect. Candour and impartiality are leading features in his history. The character given him by Mr Gibbon appears to be accurate, when he says that he is "an accurate and faithful guide, who composed the history of his own times without indulging the prejudices and passions which usually affect the mind of a contemporary."

A difference of opinion has obtained, whether or not our historian was a Christian or a Pagan. But the respectful manner in which he speaks of Pagan deities, and of the advantage of heathen auguries to foretell future events, render it abundantly evident that he was a heathen. The favourable account which he gives of the religion, manners, and fortitude of Christians, are the result of his candour and impartiality as an historian. The work of Marcellinus has passed through several editions; but that printed at Leyden in 1693, with explanatory notes, is esteemed the best. (Gen. Ammianus Marc.)