Anthemius, a seasoned military commander and senator, was elevated to the position of Emperor of the Western Roman Empire in a strategic move facilitated by the Eastern Roman Emperor Leo I. The proclamation took place in the city of Rome, a reflection of the lasting political connections and the ideological unity that still existed between the Eastern and Western Roman Empires despite their administrative divisions. Leo I aimed to ensure a strong and competent leader in the West to deal with various threats from Germanic tribes and internal dissent within the empire.

Anthemius' ascension marked a notable shift, as he was one of the few emperors of the West to receive formal recognition from his Eastern counterpart. This elevation was significant in maintaining a semblance of control and continuity in governance during a time when Roman authority was increasingly challenged by external pressures and the fragmentation of the empire. His reign was characterized by attempts to shore up defenses and bolster military presence across critical regions, especially along the frontiers where incursions were frequent.

Once in power, Anthemius faced various challenges, including managing the complex political landscape in the Western Empire which was rife with factions and rivalries. Additionally, his ties to the Eastern Empire aided in securing resources and support during his reign, though this oftentimes led to tension with local powers in the West. Despite his qualifications and connections, Anthemius' reign was ultimately a reflection of the declining power of the Western Roman Empire as it struggled with invasions, notably from the Visigoths and Vandals, and the increasing fragmentation of Roman authority.