A map of the Roman Empire under Theodosius I “the Great” (reign 379–395 CE). His reign marked a decisive turning point in Roman imperial history, bringing together political reunification, religious transformation, and institutional strain at the very moment the empire reached its last phase of formal unity. Elevated as emperor in the East after the disaster of Adrianople (378 CE), Theodosius spent much of his reign stabilizing the Balkans, managing frontier pressures, and negotiating the integration of Gothic groups into the imperial system as foederati, a pragmatic response to military shortages that reshaped Roman governance. Through civil wars against rival emperors in the West (383–388; 394 CE), he restored imperial unity, but at the cost of increased militarization and reliance on regional power brokers.
Equally transformative was Theodosius’ role in redefining the ideological foundations of the empire. With the Edict of Thessalonica (380 CE), Nicene Christianity became the official state religion, followed by legislation restricting public pagan practice (391–392 CE). These measures accelerated the fusion of imperial authority with Christian orthodoxy, reshaping law, identity, and political legitimacy. Upon Theodosius’ death in 395 CE, the empire was divided between his sons, Arcadius in the East (reign 395–408 CE) and Honorius in the West (reign 395–423 CE), a division that proved permanent. While the Eastern Roman Empire retained administrative resilience and strategic depth, the Western Empire entered a period of rapid fragmentation.
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APA Style
Netchev, S. (2026, January 29). Map of the Roman Empire under Theodosius the Great, c.395: The Last Unified Roman Empire. World History Encyclopedia. https://www.worldhistory.org/image/21558/map-of-the-roman-empire-under-theodosius-the-great/
Chicago Style
Netchev, Simeon. "Map of the Roman Empire under Theodosius the Great, c.395: The Last Unified Roman Empire." World History Encyclopedia, January 29, 2026. https://www.worldhistory.org/image/21558/map-of-the-roman-empire-under-theodosius-the-great/.
MLA Style
Netchev, Simeon. "Map of the Roman Empire under Theodosius the Great, c.395: The Last Unified Roman Empire." World History Encyclopedia, 29 Jan 2026, https://www.worldhistory.org/image/21558/map-of-the-roman-empire-under-theodosius-the-great/.
