The new Augustus divided the vast empire with his brother Valens, and this division marked the final separation of the western and eastern empires.  This arrangement continued, until the death of Valentinian in 375, when the western empire was divided between his sons, Gratian and Valentinian II.

His reign had been notable for the stemming of the invasion of the Alemanni of Gaul, the incursions of the Burgundians and the Saxons, the restoration of Britain from the attacks of the Picts and Scots, the recovery of Africa by the emperor’s general, Theodosius, and the diplomatic settlement with the approaching hordes of the Goths, who already swarmed upon the frontiers of the empire.

Under the three emperors the Roman world began to feel more severely the gradual pressure exerted by the hordes of barbarians that moved westward.  In 376 the Goths, pursued by the Huns, who had come from the steppes of China into Europe, sought the protection of Valens, who succoured them by transporting them over the Danube into Roman territory.  They repaid his clemency by uniting their arms with those of the Huns, and defeating and killing him at the battle of Hadrianople in 378.

To save the provinces from the ravages of the barbarians, Gratian appointed Theodosius, son of his father’s general, emperor of the East, and the wisdom of his choice was justified by the success of one who added a new lustre to the title of Augustus.  By prudent strategy, Theodosius divided and defeated the Goths, and compelled them to submit.

The sons of Theodosius, Arcadius and Honorius succeeded respectively to the government of the East and the West in 395.  The symptoms of decay, which not even the wise rule of Theodosius had been able to remove, had grown more alarming.  The luxury of the Romans was more shameless and dissolute, and as the increasing depredations of the barbarians had checked industry and diminished wealth, this profuse luxury must have been the result of that indolent despair which enjoys the present hour and declines the thoughts of futurity.

The secret and destructive poison of the age had affected the camps of the legions.  The infantry had laid aside their armour, and, discarding their shields, advanced, trembling, to meet the cavalry of the Goths and the arrows of the barbarians, who easily overwhelmed the naked soldiers, no longer deserving the name of Romans.  The enervated legionaries abandoned their own and the public defence, and their pusillanimous indolence may be considered the immediate cause of the downfall of the empire.

III.—­Ruin by Goth, Vandal, and Hun

The genius of Rome expired with Theodosius.  His sons within three months had once more sharply divided the empire.  At a time when the only hope of delaying its ruin depended on the firm union of the two sections, the subject of Arcadius and Honorius were instructed by their respective masters to view each other in a hostile light, to rejoice in their mutual calamity, and to embrace as their faithful allies the barbarians, whom they incited to invade the territories of their countrymen.