Origins and Early Life
Flavius Valentinianus was born in the autumn of 371 AD, the son of the reigning Western Roman emperor Valentinian I and his second wife, the empress Justina. Through his father, Valentinian II belonged to the Pannonian military dynasty that had secured supreme imperial authority in 364 AD. His older half-brother Gratian, born to Valentinian I's first wife Marina Severa, had already been elevated to the rank of Augustus in 367 AD as the designated successor. Valentinian II spent his earliest childhood in imperial residences across the western frontier and Illyricum, shielded from political rivalries by his mother. Justina was an influential figure from an aristocratic lineage connected to the former emperor Magnentius, and she exerted a profound influence over her son's upbringing and court faction.
Sources: Jones-PLRE-1, Ammianus-Res-Gestae
Elevation to Augustus
In November 375 AD, Valentinian I died suddenly while campaigning against the Quadi in Pannonia, suffering an apparent stroke at the military fortress of Brigetio. Although Gratian was already Augustus and reigning from Augusta Treverorum (modern Trier), leading Danubian generals, notably Merobaudes and Equitius, feared military instability and the potential for army disaffection. On 22 November 375 AD, the military gathered at the encampment of Aquincum (modern Budapest) and acclaimed the four-year-old Valentinian II as Augustus. Gratian, presented with a fait accompli, astutely chose to ratify the army's choice rather than risk civil war. The Western empire was nominally partitioned between the brothers: Gratian maintained direct oversight of the northern Gallic and Britannic frontiers, while the young Valentinian II, guided by Justina, was assigned the administration of Italy, Illyricum, and North Africa.
Sources: Jones-PLRE-1, Ammianus-Res-Gestae
Imperial Reign and Internal Conflict
The administrative core of Valentinian II's realm was established at Mediolanum (Milan), where actual executive governance rested with Justina and leading court officials. In 383 AD, the stability of the Western empire collapsed when the general Magnus Maximus revolted in Roman Britain and crossed into Gaul, resulting in the overthrow and murder of Gratian. Maximus established his imperial seat at Trier, leaving Valentinian II in an exceptionally precarious position in Italy. Justina conducted delicate diplomatic negotiations with Maximus, utilizing Bishop Ambrose of Milan as an envoy to stall further invasion while seeking aid from the Eastern Augustus, Theodosius I. The uneasy peace ruptured in 387 AD when Maximus crossed the Alps to seize Italy. Valentinian II and his family fled Mediolanum by sea, taking refuge at Thessalonica under the protection of Theodosius I. Theodosius subsequently launched a major military campaign against Maximus, defeating and executing the usurper at Aquileia in 388 AD. Theodosius then restored Valentinian II to nominal western rule, transferring him to Vienne in Gaul while retaining effective administrative and military authority under the Frankish general Arbogast.
Government and Court Politics
Valentinian II's administration was throughout his life characterized by court-dominated regency and reliance on formidable generals. During his youth in Mediolanum, the imperial court was overseen by civilian ministers and the guidance of his mother Justina. Following the victory over Maximus in 388 AD, Theodosius I sought to secure the Gallic territories by placing Valentinian II under the protective guardianship of Arbogast, the magister militum. Arbogast systematically concentrated power into his own hands, filling military and administrative offices with his loyal Frankish and Gallic confederates. The teenage emperor found himself increasingly isolated within his palace at Vienne, effectively reduced to a titular figurehead. When Valentinian II attempted to assert his sovereignty in early 392 AD by presenting Arbogast with a written decree of dismissal during a public council, the general insolently tore the document to shreds, retorting that his command was not derived from Valentinian and could not be revoked by him.
External Affairs and Dynastic Alliances
Foreign policy during the reign of Valentinian II was largely managed by external arbiters, as the court prioritized internal survival. On the Danubian and Alpine frontiers, defensive postures were maintained through alliances and diplomacy conducted under the shadow of larger imperial conflicts. In 387 AD, diplomatic overtures to the court of Constantinople culminated in a dynastic alliance when Theodosius I married Valentinian II's sister Galla. This marriage cemented Theodosius's intervention against Magnus Maximus on behalf of the young emperor. On the Rhine frontier, Arbogast conducted vigorous campaigns against Frankish tribes in 389 AD and 392 AD, reinforcing border defenses in Gaul and demonstrating military capability, though these successes served primarily to consolidate Arbogast's personal prestige and leverage rather than bolster Valentinian II's direct authority.
Religious Tensions and Cultural Disputes
The reign witnessed intense religious and cultural controversies that defined the late fourth century Roman world. The imperial court in Mediolanum adhered to Homoean (Arian) Christianity, championed vigorously by Justina, which put the court into direct conflict with the fervently Nicene local bishop, Ambrose of Milan. In 385 and 386 AD, Justina demanded that a basilica in Milan be assigned for Arian worship, provoking widespread civil unrest and a standoff wherein Ambrose barricaded himself in the church alongside a devoted congregation. Valentinian II's government ultimately yielded to the bishop, demonstrating the rising ascendancy of ecclesiastical authority over imperial will. Concurrently, pagan aristocrats led by Quintus Aurelius Symmachus, the urban prefect of Rome, petitioned Valentinian II in 384 AD to restore the Altar of Victory to the Senate house. Despite Symmachus's eloquent appeal to Roman tradition, Ambrose intervened with letters threatening Valentinian with excommunication, compelling the young emperor to reject the petition.
Sources: Jones-PLRE-1, Williams-Friell-Theodosius
Death and Historical Legacy
Valentinian II's life ended mysteriously on 15 May 392 AD, when he was discovered hanged in his imperial residence at Vienne at approximately twenty years of age. Arbogast and his associates reported the death as a suicide, claiming the young emperor had succumbed to despair over his lack of control. However, many contemporary observers and later historians, including Zosimus and Philostorgius, suspected Arbogast of arranging the emperor's assassination or driving him to his death. Following his death, Ambrose delivered a poignant funeral oration, De obitu Valentiniani, praising his moral character. Arbogast, unwilling to assume the purple directly as a Frank, elevated the rhetorician Eugenius to the throne, precipitating a catastrophic civil war that concluded with Theodosius I's victory at the Battle of the Frigidus in 394 AD. Valentinian II's tragic reign highlighted the structural vulnerability of child emperors and the decisive transfer of western imperial power into the hands of barbarian generals.
Sources: Jones-PLRE-1, Zosimus-Historia-Nova, Williams-Friell-Theodosius
References
- The Prosopography of the Later Roman Empire, Volume 1. p. 934
- Res Gestae. Book 30, Chapter 10
- Historia Nova. Book IV
- Theodosius: The Empire at Bay. pp. 41-65