VALENTINIAN I., Roman emperor of the West from A.D. 364 to 375, was born at Cibalis, in Pannonia. He had been an officer of the guard under Julian and Jovian, and had risen high in the imperial service. Of robust frame and distinguished appearance, he possessed great courage and military capacity. He was chosen emperor in his forty-third year by the officers of the army at Nicaea in Bithynia in 364, and shortly after-wards named his brother Valens (q.v.) colleague with him in the empire. The two brothers, after passing through the chief cities of the neighbouring district, arranged the partition of the empire at Naissus (Nissa) in Upper Moesia. As emperor of the West, Valentinian took Italy, Illyricum, Spain, the Gauls, Britain and Africa, leaving to Valens the eastern half of the Balkan Peninsula, Greece, Egypt, Syria and Asia Minor as far as Persia. During the short reign of Valentinian there were wars in Africa, in Germany and in Britain, and Rome came into collision with barbarian peoples of whom we now hear for the first time—Burgundians, Saxons, Alamanni. The emperor’s chief work was guarding the frontiers and establishing military positions. Milan was at first his headquarters for settling the affairs of northern Italy; next year (365) he was at Paris, and then at Reims, to direct the operations of his generals against the Alamanni. This people, defeated at Scarpona (Charpeigne) and Catelauni (Châlons-sur-Marne) by Jovinus, were driven back to the German bank of the Rhine, and checked for a while by a chain of military posts and fortresses. At the close of 367, however, they suddenly crossed the Rhine, attacked Moguntiacum (Mainz) and plundered the city. Valentinian attacked them at Solicinium (Sulz in the Neckar valley or Schwetzingen) with a large army, and defeated them with great slaughter, but his own losses were so considerable that he abandoned the idea of following up his success. Later, in 374, he made peace with their king, Macrianus, who from that time remained a true friend of the Romans. The next three years he spent at Trier, which he chiefly made his headquarters, organizing the defence of the Rhine frontier, and personally superintending the construction of numerous forts. During his reign the coasts of Gaul were harassed by the Saxon pirates, with whom the Picts and Scots of northern Britain joined hands, and ravaged the island from the wall of Antoninus to the shores of Kent. In 368 Theodosius was sent to drive back the invaders; in this he was completely successful, and established a new British province, called Valentia, in honour of the emperor. In Africa the Moorish prince, Firmus, raised the standard of revolt, being joined by the provincials, who had been rendered desperate by the cruelty and extortions of Count Romanus, the military governor. The services of Theodosius were again requisitioned. He landed in Africa with a small band of veterans, and Firmus, to avoid being taken prisoner, committed suicide. In 374 the Quadi, a German tribe in what is now Moravia and Hungary, resenting the erection of Roman forts to the north of the Danube in what they considered to be their own territory, and further exasperated by the treacherous murder of their king, Gabinius, crossed the river and laid waste the province of Pannonia. The emperor in April of the following year entered Illyricum with a powerful army, but during an audience to an embassy from the Quadi at Brigetio on the Danube (near Pressburg) died in a fit of apoplexy. His general administration seems to have been thoroughly honest and able, in some respects beneficent. If he was hard and exacting in the matter of taxes, he spent them in the defence and improvement of his dominions, not in idle show or luxury. Though himself a plain and almost illiterate soldier, he was a founder of schools, and he also provided medical attendance for the poor of Rome, by appointing a physician for each of the fourteen districts of the city. He was an orthodox Catholic, but he permitted absolute religious freedom to all his subjects. Against all abuses, both civil and ecclesiastical, he steadily set his face, even against the increasing wealth and worldliness of the clergy. The great blot on his memory is his cruelty, which at times was frightful, and showed itself in its full fierceness in the punishment of persons accused of witchcraft, soothsaying or magical practices.
See Ammianus Marcellinus xxv.-xxx.; Gibbon, Decline and Fall, chap. 25; T. Hodgkin, Italy and her Invaders, bk. i. chap. 3; H. Schiller, Geschichte der römischen Kaiserzeit (Gotha, 1883–87), bk. iii. chap. iv. 27–30; H. Richter, Das weströmische Reich (Berlin, 1865), pp. 240–68.
After his death, his son, Valentinian II., an infant of four years of age, with his half-brother Gratian (q.v.) a lad of about seventeen, became the emperors of the West. They made Milan their home; and the empire was nominally divided between them, Gratian taking the trans-Alpine provinces, whilst Italy, Illyricum in part, and Africa were to be under the rule of Valentinian, or rather of his mother, Justina. Justina was an Arian, and the imperial court at Milan pitted itself against the Catholics, under the famous Ambrose, bishop of that city. But so great was his popularity that the court was decidedly worsted in the contest, and the emperor’s authority materially shaken. In 387 Magnus Maximus (q.v.), who had commanded a Roman army in Britain, and had in 383 (the year of Gratian’s death) made himself master of the northern provinces, crossed the Alps into the valley of the Po and threatened Milan. The emperor and his mother fled to Theodosius, the emperor of the East and husband of Galla, Valentinian’s sister. Valentinian was restored in 388 by Theodosius, through whose influence he was converted to Orthodox Catholicism. Four years later he was murdered at Vienne in Gaul, probably at the instigation of his Frankish general Arbogast, with whom he had quarrelled.
See Gibbon, Decline and Fall, chap. 27; Schiller, Geschichte der römischen Kaiserzeit, bk. iii. vol. iv. pp. 32, 33; L. Ranke, Weltgeschichte, bk. iv. vol. i. chap. 6; and especially H. Richter, Das weströmische Reich unter den Kaisern Gratian, Valentinian II. and Maximus (Berlin, 1865), pp. 577–650, where full references to authorities are given.