Anastasius I (431-518), also known as Anastasius Dicorus, was born into an Illyrian family. After Emperor Zeno's death in 491 CE, many citizens of the empire wanted both a Roman and an Orthodox Christian emperor. In response, Zeno's widow and Emperor Leo I's daughter Ariadne turned to Anastasius, who was in his sixties when he married Ariadne and ascended to the throne.

Anastasius soon had to deal with the usurper Longinus, brother of the late Zeno, engaging in the Isaurian War and defeating Longinus in 497. He later fought against the Sassanid Empire in the Anastasian War, the war raging from 502 until 506 when peace was made and the status quo returned to. He also had to contend with invasions by Bulgars and Slavs into the Balkan provinces.

Overall, Anastasius' reign was marked for its recognisable accomplishments in terms of bureaucracy and economy. His reforms to taxing, government corruption and new forms of currency resulted in the imperial government being left with a sizable budget surplus by the time he died in 518, aged 87.