Peoples from across the Rhine and Danube had asked to be settled within the Roman Empire before. Now under the leadership of Alavivus and Fritigern, the Thervingi offered themselves as a bulwark against the Huns (Zosimus New History 20.3). When the Gothic request came, Valens was at Antioch, preparing for another campaign against the Sassanian Persians. However, in 378, Valens returned to Constantinople to deal with a threat that had proved much more serious than he imagined (Ammianus, 31.11.1). The Goths had rebelled after Roman mistreatment and, having defeated the two previous Roman forces sent against them, were left free to overrun Thrace. Socrates (Ecclesiastical History 4.38) tel Is us that Valens marched out against the Goths without waiting for reinforcements from his nephew, Gratian, Emperor of the West. He departed Constantinople with his commander, the magister militum Sebastianus, and his combined forces ready to hunt the Goths. Ammianus gives little detail of the army Valens took with him, only that it was numerous and was composed of different elements, including parts of the comitatus praesentalis (the army in the imperial presence), units of the comitatus of Thrace, and units of imperial scholae cavalry.
Cautioned by ambushes of his raiding bands, Fritigern recalled his raiders to Cabyle and withdrew. Gratian wrote to Valens, informing his uncle of his own victory over the Alemanni
