Large groups of Tervingian Goths (and others) sought refuge from the Huns and were allowed by imperial authorities to cross the Danube into Roman territory. Mistreatment and supply failures helped turn the refugees into armed rebels, igniting the Gothic War (376–382).
The Eastern Roman field army suffered a catastrophic defeat by Gothic forces near Adrianople, and Emperor Valens was killed. The battle exposed Roman vulnerabilities and shaped later reliance on federate troops and negotiated settlements with barbarian groups.
Peace was declared between Theodosius I’s government and the Goths, incorporating Gothic groups as foederati and granting them land inside the empire under their own leaders. This arrangement institutionalized large, semi-autonomous barbarian communities within Roman borders.
Theodosius I defeated the western usurpers Eugenius and Arbogast in a major civil war battle that used substantial federate forces. The heavy losses and continuing internal power struggles weakened the West on the eve of intensified external pressures.
Under pressure from Gothic incursions, the Western imperial residence moved to Ravenna, whose marshy setting and access to the sea made it easier to defend. The move also contributed to a growing disconnect between the court and crises in Gaul and along the Rhine.
Alaric’s Visigoths invaded Italy; Stilicho and imperial forces defeated them at Pollentia, forcing a withdrawal. The episode showed how quickly mobile barbarian armies could threaten the imperial court in Italy.
Following Stilicho’s fall, Alaric invaded again and began the first of several sieges of Rome (late 408). The sieges exposed the West’s inability to protect its symbolic and administrative center while the court remained entrenched at Ravenna.
After devastating parts of Gaul, Vandals, Alans, and Suebi crossed into Hispania (late September/early October 409 in most reconstructions). Their movement helped break Roman fiscal and military systems in Spain and reduced the West’s ability to draw resources from the region.
In May 429, Vandal forces under Geiseric crossed from Spain to North Africa. The subsequent conquest threatened the Western Empire’s grain supply and tax base, making recovery in the West far more difficult.
Vandal forces looted Rome for about two weeks in June 455, following political upheaval and the collapse of effective defense. The sack further eroded imperial legitimacy and highlighted the strategic consequences of losing North Africa.
The Germanic commander Odoacer overthrew and deposed Romulus Augustulus at Ravenna, conventionally marking the end of the Western Roman Empire. Odoacer ruled Italy as king, while imperial authority continued in the Eastern Roman Empire.
Fall of the Western Roman Empire: Barbarian Invasions to the Deposition of Romulus Augustulus (376–476 CE)
