VALENTINIAN III., emperor of the West from 425 to 455, the son of Constantius and Placidia, daughter of the great Theodosius. He was only six years of age when he received the title of Augustus, and during his minority the conduct of affairs was in the hands of his mother, who purposely neglected his education. His reign is marked by the dismemberment of the Western Empire; the conquest of the province of Africa by the Vandals in 439; the final abandonment of Britain in 446; the loss of great portions of Spain and Gaul, in which the barbarians had established themselves; and the ravaging of Sicily and of the western coasts of the Mediterranean by the fleets of Genseric. As a set-off against these calamities there was the great victory of Aetius over Attila in 451 near Chalons, and his successful campaigns against the Visigoths in southern Gaul (426, 429, 436), and against various invaders on the Rhine and Danube (428-31). The burden of taxation became more and more intolerable as the power of Rome decreased, and the loyalty of her remaining provinces was seriously impaired in consequence. Ravenna was Valentinian's usual residence; but he fled to Rome on the approach of Attila, who, after ravaging the north of Italy, died in the following year (433). In 454 Aetius, between whose son and a daughter of the emperor a marriage had been arranged, was treacherously murdered by Valentinian. Next year, however, the emperor himself was assassinated by two of the barbarian followers of Aetius. He not merely lacked the ability to govern the empire in a time of crisis, but aggravated its dangers by his self-indulgence and vindictiveness.
Our chief original sources for the reign of Valentinian III. are Jordanes, Prosper's Chronicles, written in the 6th century, and the poet Apollinaris Sidonius. See also Gibbon, Decline and Fall, chaps. 33-35; J. B. Bury, Later Roman Empire, bk. ii. chaps. 6-^8; E. A. Freeman, " Tyrants of Britain, Gaul and Spain " (Eng. Hist. Review, January 1886), and " Aetius and Boniface " (ibid., July 1887).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)