The Rise of a Soldier-Emperor

In January 395 AD, the Roman Emperor Theodosius I died at 48—an untimely death by ancient standards. Unlike many of his predecessors, he succumbed not to battle or assassination but to illness, likely exacerbated by 16 years of relentless military campaigns and administrative burdens. Theodosius had spent his reign crisscrossing the empire, from the Danube to Gaul, defending its borders against invading Goths, usurpers, and rival factions. His death in Milan followed a grueling campaign against the Gallic usurper Eugenius, underscoring his commitment to the traditional Roman ideal of the Imperator—a title originally reserved for victorious generals who safeguarded the realm.

Theodosius was the last emperor to embody this martial ethos fully. His reign (379–395 AD) bridged two eras: the waning days of a unified Roman Empire and the dawn of its irrevocable division. Though history remembers him as the ruler whose death formalized the split between East and West, his intentions were far more nuanced.

Theodosius and the Christian Empire

Theodosius earned the epithet “the Great,” much like Constantine before him, but for starkly different reasons. Constantine, in the early 4th century, had legalized Christianity through the Edict of Milan (313 AD), granting it parity with pagan cults. Theodosius, by contrast, enforced Christian orthodoxy with an iron fist. His 380 AD Edict of Thessalonica declared Nicene Christianity the state religion, banning pagan sacrifices and suppressing dissenting sects like Arianism.

This shift was championed by powerful clerics like Ambrose, Bishop of Milan, who famously confronted Theodosius over the Massacre of Thessalonica (390 AD)—a rare moment of imperial submission to ecclesiastical authority. At Theodosius’s funeral, Ambrose delivered a stirring eulogy, framing the emperor’s legacy as divine: “Theodosius lives on in his sons! His celestial gaze guards them, and his spirit demands your loyalty!”

The Illusion of Unity: Succession and Division

Theodosius left the empire to his two young sons: 18-year-old Arcadius in the East and 10-year-old Honorius in the West. Modern historians often cite 395 AD as the official partition of Rome, but Theodosius likely envisioned a continuation of the diarchy system—a pragmatic division of administrative duties, not sovereignty. Since Diocletian’s Tetrarchy (293 AD), shared rule had been a survival tactic against external threats. Theodosius entrusted both heirs to his trusted general, Stilicho, a half-Vandal military genius, signaling his hope for cohesion.

Yet the plan unraveled. Arcadius’s court in Constantinople, influenced by anti-Western factions, resisted Stilicho’s oversight. Meanwhile, Honorius’s reign in Ravenna (the Western capital) became a puppet show, with Stilicho wielding real power until his execution in 408 AD. The brothers, raised in palace isolation, lacked the martial charisma of their father. As Italian historian Roberto Paribeni noted, “Their legitimacy stemmed solely from their bloodline—not from the Senate’s approval or the army’s acclaim.”

The Slow Death of a Superpower

The East-West divide was less a clean break than a creeping divergence. The Eastern Empire, wealthier and more urbanized, gradually adopted Greek customs, while the West fractured into feuding Gothic kingdoms. Arcadius ruled the East for 13 years; Honorius clung to the Western throne for 28, though his reign saw the Sack of Rome by Alaric’s Visigoths (410 AD)—a psychological blow from which the West never recovered.

Theodosius’s death exposed the fragility of imperial unity. His sons’ reigns marked the end of the Senatus Populusque Romanus (SPQR) compact, replacing it with a Christianized autocracy where “divine right” trumped civic tradition. The Eastern Empire endured as Byzantium for another millennium, but the West’s collapse by 476 AD underscored the limits of dynastic loyalty in a world of shifting allegiances.

Legacy: The Unintended Architect of Two Worlds

Theodosius’s legacy is a paradox. He sought to preserve Rome through faith and force, yet his policies accelerated its fragmentation. His elevation of Christianity reshaped European identity, while his reliance on “barbarian” generals like Stilicho foreshadowed medieval feudalism. The silver dish depicting Theodosius with his sons—now in Madrid’s Royal Academy—captures a fleeting moment of unity, masking the turmoil ahead.

In the end, Theodosius was the last emperor to rule both halves of Rome in fact as well as name. His death didn’t just divide an empire; it birthed two civilizations—one destined to fade into legend, the other to evolve into Byzantium. For all his zeal, even the “Great” could not defy the tides of history.