In 376, the Goths led by Alavivus and Fritigern asked to settle in the Eastern Roman Empire after being displaced by Huns. Emperor Valens allowed them to establish themselves as allies known as foederati once they crossed the Danube river. Dishonesty from provincial commanders Lupicinus and Maximus caused the newcomers to revolt after suffering many hardships. Valens then asked Gratian, the western emperor, for reinforcements to fight the Goths. Gratian sent general Frigeridus with troops and Richomeres, leader of his guards. For two years preceding the battle there was a series of running battles with no clear victories for either side. In 378, Valens decided to take control himself and assembled additional troops from Syria and Gaul reserves. He left Antioch for Constantinople arriving on the 30th of May. Sebastianus arrived from Italy to reorganize Roman armies already in Thrace. Sebastianus picked 2,000 legionaries and marched towards Adrianople. Along the way they ambushed small detachments of Goths. Fritigern assembled forces at Nicopolis and Beroe to deal with the threat. Much of Gratian's army was in Pannonia where they were attacked across the Rhine by Lentienses. After defeating the Lentienses near Argentaria, Gratian's army traveled east partly by sea and overland. Upon learning of Sebastianus's success against Goths and Gratian's victory over Lentienses, Valens moved his army from Melantias to Adrianople. On the 6th of August reconnaissance informed Valens that approximately 10,000 Goths were advancing toward Adrianople from 25 kilometers north. Valens fortified his camp with ditches and ramparts. Richomeres carried a letter asking Valens to wait for reinforcements before engaging battle. Valens' officers also recommended waiting but he decided to fight without waiting. The Goths watched Romans closely and on the 8th of August Fritigern sent an emissary proposing peace and alliance. Valens rejected these proposals due to supposed numerical superiority. His estimates neglected part of Gothic cavalry that had gone extended distances to forage.
Army Compositions
Valens' army may have included troops from three Roman field armies: Army of Thrace based in eastern Balkans, 1st Army in Emperor's Presence, and 2nd Army in Emperor's Presence. Both armies in Emperor's Presence were normally based at Constantinople in peacetime but committed to Persian frontier in 376. They were sent west in 377, 378. The entire force consisted of seven legions including Legio I Maximiana and imperial auxiliaries of 700 to 1000 men each. Cavalry was composed of mounted archers known as sagittarii and Scholae imperial guard. Ammianus Marcellinus makes references to Legions of Lanciarii and Mattiarii listed as legiones palatinae. Some claim Mattiarii may have been allied forces while others suggest they refer to mace-armed infantry. A battalion of Batavians was apparently held in reserve and fled when comes named Victor attempted to bring them into battle. Scutarii shielded cavalry and archers operated under command of Bacurius the Iberian possibly as allied auxiliary troops from Caucasian Iberia. Ricomer Frankish Comes of Gratian's Domestici offered to act as hostage to facilitate negotiations when Equitus refused. Sebastianus arrived from Italy clearly operating as one of Valens' generals before being killed in battle. Victor master-general of cavalry was Sarmatian by birth who led officers counseling waiting for Gratian. Equitius a relation of Valens was tribune and high steward of palace who refused acting as hostage after escaping captivity in Dibaltum. Bacurius native and possibly prince of Iberia commanded archers and scutarii with Cassio that accompanied Ricimer as hostage. Traianus was described as illustrious man whose death in battle was great loss. Victor came tried to bring Batavian reserve battalion into action. Saturninus magister militum vacans referred to as able to stay alive by retreating. Potentius tribune of Promoti branch of cavalry son of Ursicinus former commander fell in flower of his age respected by all persons of virtue. Thirty five tribunes including those of units and staff were killed though presumably more survived.