The elevation of Flavius Theodosius to the rank of Augustus marks a pivotal moment in the Roman Empire's history. In Sirmium, Emperor Gratian recognized Theodosius's capabilities as a military leader, particularly in the context of the increasing challenges faced by the Eastern provinces due to internal strife and external threats from various tribes. At this time, the Roman Empire was dealing with pressures from the Gothic tribes and other barbarian invasions, leading to instability and unrest. Gratian’s decision to elevate Theodosius aimed to consolidate power in the East and provide a strong leadership presence to effectively manage these challenges.

Theodosius's elevation was not only a political maneuver but also a strategic one. As Augustus, Theodosius had the authority to enact military strategies and administrative reforms necessary for maintaining stability in the Eastern provinces. His rule would be characterized by his efforts to secure the frontiers and bolster the military against external threats, all while navigating the complex politics of an empire that was becoming increasingly divided. Theodosius's subsequent campaigns would solidify his reputation as a competent leader, showcasing his ability to unify disparate factions within the empire.

Theodosius's accession to the rank of Augustus led to significant changes in the governance of the Eastern Roman Empire. His policies and military campaigns would pave the way for the eventual establishment of Christianity as the state religion of the Roman Empire, thus altering the course of religious and cultural history in the region. His reign is often viewed as a turning point that influenced the administrative and military structures of the empire in its later years.