The Greuthungi, led by Alatheus and Saphrax, displaced by the predations of the Huns and Alans, request asylum within the Roman Empire. They are refused. The Roman frontier forces stretched to the breaking point, they slip across the Danube and unite with Fritigern. With their situation critical and desperately short of food, discontent is rising amongst the Goths.
The Romans fail to disarm the Visigoths, bungle administration of the refugees, and mistreat them, taking some of their children as slaves. The Goths break out of their containment area along the Danube and strike south towards the low-lying fertile region near Marcianople (Bulgaria). Although defying the local Roman officials, they are not in open revolt.
Lupicinus, Comes (Count) of Thrace, tries to bring the Visigoths back under control. He invites Fritigern and the Gothic leaders to a banquet, letting them believe that in addition to food and drink, they can discuss provisions for their people. During the feast Lupicinus tries to assassinate the Gothic delegation. Fritigern escapes and the Goths begin looting and burning the farms and Roman villas near Marcianople.
Lupicinus attacks the Visigoths 9 miles outside Marcianople with hastily gathered local troops. His force (5,000 men) is annihilated and the Goths equip themselves with Roman armour and weapons. Fritigern marches south towards Adrianople (Turkey).
Fearing they will join Fritigern, Roman troops of Gothic origin stationed in Adrianople are ordered by Valens to move east. The soldiers request a two-day delay to prepare and ask for food and money for the journey. However, the chief magistrate of Adrianople refuses and the Goths break out in open rebellion. They inflict heavy casualties among the citizens. Arming themselves with Roman equipment, they join forces with Fritigern.
Winter – Fritigern attempts an unsuccessful siege of Adrianople. His troops try to storm the city walls, but abandon the attacks and break into small bands, better able to forage and feed themselves. Roman prisoners switch sides and give the Goths a valuable source of local intelligence.
Emperor Valens requests his nephew Gratian to send Roman troops against the Goths. He responds by sending the ageing General Frigeridus with elite reinforcements that Ammianus calls ‘Pannonian and Transalpine auxiliaries (Pannonicis et Transalpinis auxiliis).’ Gratian sends also Richomeres, his Frankish commander of household troops (comes domesticorum), at the head of a number of troops drawn from the Gallic field army.
The Goths (possibly Greuthungi) make an alliance with some of the Huns and Alans along the Danube, and entice them across the river. With the balance of power now shifted Saturninus concentrates his forces to avoid his outposts being overrun. This opens the passes, allowing the Goths, Huns and Alans to break out into the lowlands of southern Thrace.
Autumn – Bands of predatory "barbarians" spread throughout the province in search of food, supplies and booty. Most Roman troops are bottled up in the towns. Some elite units remain in the field and skirmish with the Goths. One such action takes place outside the town of Dibaltum. The Scutarii heavy cavalry is destroyed in a mad charge against the Goths.
The Goths, now seeking a military victory to force the Empire to make terms, aim to dislodge the army of Frigeridus from Beroea. He withdraws over the Succi (Ihtiman) Pass back to Illyrium, and reports to Gratian that an expedition by the main imperial armies is required to repulse the Goths in Thrace.
Valens concludes a peace with the Persian Empire and leaves enough troops to defend the eastern frontier. The Saracens under Queen Mavia revolt and devastate a swath of territory stretching from Phoenicia and Palestine as far as the Sinai (Egypt). Valens successfully brings the uprising under control.
July – Frigeridus, Roman general, fortifies the Succi (Ihtiman) Pass to prevent the "barbarians" from breaking out to the north-west (Pannonia).
Gratian sets out from Lauriacum (Austria) with a body of light armed troops. His force is small enough to travel by boat down the Danube. He halts for four days at Sirmium (Serbia) suffering from fever.
August – Gratian continues down the Danube to the "Camp of Mars" (frontier fortress near modern Niš), where he loses several men in an ambush by a band of Alans.
Fritigern strikes south from Cabyle, following the Tundzha River towards Adrianople, and tries to get behind the supply lines to Constantinople.
Roman reconnaissance detects the Goths. Valens, already west of Adrianople, returns back and establishes a fortified camp outside the city.
The Goths, with their wagons and families vulnerable to attack, withdraw back to the north. Roman scouts fail to detect the Greuthungi cavalry foraging further up the Tundzha valley.
Fritigern sends a Christian priest to the Roman camp with an offer of terms and a letter for Valens. The peace overtures are rejected.
^Imperatores Valentinianus, Valens, Gratianus . Ad barbaricum transferendi vini et olei et liquaminis nullam quisquam habeat facultatem ne gustus quidem causa aut usus commerciorum. * VALENTIN. VALENS ET GRAT. AAA. AD THEODOTUM MAG. MIL.