76 THE HISTORY OF MEDIEVAL EUROPE They asked permission to settle south of the Danube, prom- ising not to plunder and to aid the emperor in defending the frontier. They were allowed to cross the river, but then the imperial officials failed to supply them with food until they could grow crops for themselves, and in other ways ill-treated them. In consequence they began to ravage the country-side and before long crossed the Balkan Mountains and entered Thrace, leaving the Danube frontier behind them open to any one who cared to follow. Valens, who already had experienced quite enough trouble for one reign from would-be assassins and usurpers, conspiracies and rebellions, and wars with Persia in the Far East, was now called upon to face this new danger. Before he arrived, there had been considerable indecisive righting with the Goths, whose numbers by now had been further swelled by bands of Alani and Huns, who now, however, fought as their allies and to whose hideous appearance and coarse manners the Goths seem to have quickly reconciled them- selves. With the arrival of Valens a pitched battle was fought, in which the emperor himself, his leading generals, and the greater part of his army were slain. The Goths, however, were unable to take either the city of Adrianople, near which the defeat had occurred, or the capital, Constan- tinople, against which they next marched. But their vic- tory left them permanently within the Empire, where in the Balkan peninsula they and other barbarians who sooner or later followed in behind them formed a wedge separating the eastern and western halves of the Empire. Therefore, it has long been the custom to date the beginning of success- ful barbarian invasions or migrations of the peoples from the battle of Adrianople in 378. Gratian, a boy in his teens, had become emperor in the West on the death of his father, Valentinian ; on the death Reigns of of his uncle, Valens, he named as his associate in Theodosius the East Theodosius, son of the general who had the Great fought for his father. Huns, Ostrogoths, and Alani came westward, but Gratian satisfied them for the time by abandoning to them Upper Mcesia and Pannonia,
