378

By place

Roman Empire

• Spring - Emperor Valens returns to Constantinople and mobilises an army. He appoints Sebastianus, newly arrived from Italy, as magister militum to reorganize the Roman armies in Thrace.
• February - The Lentienses cross the frozen Rhine and raid the countryside. They are driven back by Roman auxilia palatina, who defend the western frontier.
• May - Battle of Argentovaria: Emperor Gratian is forced to recall the army he has sent East. The Lentienses are defeated by Mallobaudes near Colmar. Gratian gains the title Alemannicus Maximus.
• Gothic War: Valens sends Sebastian with a body of picked troops to Thrace and renews the guerrilla war against the Goths. He chases down small groups of Gothic raiders around Adrianople.
• Fritigern concentrates his army at Cabyle. The Goths are mainly centred in the river valleys south of the Balkan Mountains, around the towns of Beroea, Cabyle and Dibaltum.
• July - Frigeridus, Roman general, fortifies the Succi Pass to prevent the "barbarians" from breaking out to the north-west.
• Gratian sets out from Lauriacum 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 suffering from fever.
• August - Gratian continues down the Danube to the "Camp of Mars", 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 Military [supply chain management|supply lines] to Constantinople.
• Roman reconnaissance detects the Goths. Valens, already west of Adrianople, turns 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.
• August 9 - Battle of Adrianople: Valens leads an elite Roman army to Thrace to confront revolts, but is defeated.
• The Goths attack Adrianople; they attempt to scale the city walls with ladders but are repelled by the defenders, who drop lumps of masonry.
• The Goths, supported by the Huns, move on to Constantinople. Their progress is checked by the Saracens, recruited from Arab tribes who control the eastern fringes of the empire.
• October - The Greuthungi, faced with food shortages, split off and move west into Pannonia. Followed by their families, they raid villages and farmland.

Mesoamerica

• Siyaj K'ak' begins to replace Mayan kings with relatives of Spearthrower Owl, emperor of Teotihuacan.
• Siyaj K'ak' conquers Waka on January 8.
• Siyaj K'ak' conquers Tikal on January 16.
• Siyaj K'ak' conquers Uaxactun.

By topic

Architecture

• Valens completes the aqueduct of Constantinople begun by Constantine I.

Religion

• Gregory of Nazianzus is ordained bishop of Constantinople.
• Pope Damasus I is accused of adultery but is exonerated by Gratian.