The year was 375 AD. Valentinian I, the reigning Emperor of the West, had died, leaving his son Gratian to inherit the throne. However, Gratian’s sole rule was short-lived, as just five days later, a shockwave rippled through the empire.

The Danubian legions stationed at Aquincum (present-day Budapest) took matters into their own hands, boldly proclaiming the four-year-old Valentinian II, Gratian’s half-brother, as co-Augustus. This audacious move was a calculated power play, driven by the Danubian forces’ long-standing grievances against the central government.

The Fault Lines of Favoritism:

Gratian, raised alongside Germanic auxiliaries, heavily favored these troops, causing resentment among the Danubian legions. Despite their crucial role in defending the Danube frontier – a vital bulwark against barbarian incursions – they felt their contributions were undervalued by Gratian’s administration. Elevating Valentinian II, a symbol of their region, was their way of demanding recognition and a greater stake in the empire’s future.

Gratian’s Dilemma: Civil War or Compromise?

The proclamation of Valentinian II caught Gratian off guard. He faced a stark choice: challenge the legions and risk a devastating civil war, or accept his half-brother as co-ruler and concede some power. With the empire’s stability hanging in the balance, Gratian chose the pragmatic path.

A Precarious Peace and the Rise of Court Intrigue:

While this decision averted immediate conflict, it laid the foundation for future power struggles. Gratian likely hoped to maintain control as Valentinian II matured, but the situation was far from stable. The presence of two emperors, one a mere child, would inevitably invite challenges to authority.

Adding fuel to the fire, the women of the imperial court entered the fray. Gratian’s mother, Severa, and Valentinian II’s mother, Justina, both ambitious and influential figures, saw an opportunity to advance their own agendas. Their rivalry added a layer of complexity to the already tense political landscape.

A Turning Point for the Western Roman Empire:

The co-rulership of Gratian and Valentinian II marked a turning point in the Western Roman Empire’s history. It exposed deep-seated divisions, highlighted the weakening grip of the central government, and showcased the growing power of regional military forces. This precarious balance of power would ultimately pave the way for further instability and internal conflict, contributing to the empire’s eventual decline.

Seeds of Future Discord

Gratian’s acceptance of Valentinian II as co-emperor, while maintaining short-term stability, sowed the seeds of future discord. The Danubian legions, having flexed their military muscle, would be more likely to challenge central authority in the years to come. Additionally, the presence of a child emperor on the throne created a power vacuum that ambitious court figures, like Justina, would be eager to exploit. The delicate balance of power between the two emperors and their mothers would be a source of constant tension and political maneuvering.

A Weakened Empire

The co-rulership also highlighted the weakening control of the central Roman government. The Danubian legions’ ability to dictate the terms of Valentinian II’s ascension demonstrated the declining authority of the emperor in distant provinces. This regional power imbalance would make it increasingly difficult for the central government to maintain control over its vast territories and effectively respond to external threats.

A Foreshadowing of Fragmentation

The very concept of having two emperors, one for each half of the Roman Empire, foreshadowed the eventual fragmentation of the empire into separate Western and Eastern halves. While this division wouldn’t occur for several decades, the events of 375 AD marked a significant step towards this outcome. The co-rulership highlighted the growing political and cultural differences between the eastern and western regions, setting the stage for their eventual separation.