Who was Justinian the first and what did he do for the Roman Empire?

Justinian I 483–565, Byzantine emperor (527–65), nephew and successor of Justin I Justin I, c.450–527, Byzantine emperor (518–27); successor of Anastasius I. He was chief of the imperial guard and became emperor when Anastasius died. He was responsible for much imperial policy during his uncle's reign. Soon after becoming emperor, Justinian instituted major administrative changes and tried to increase state revenues at the expense of his subjects. Justinian's fiscal policies, the discontent of the Monophysites at his orthodoxy, and the loyalty of the populace to the family of Anastasius I produced the Nika riot (532), which would have cost Justinian his throne but for the firmness of his wife, Empress Theodora Theodora and the aid of his great generals, Belisarius Belisarius and Narses Narses c.478–c. Justinian, through Belisarius and Narses, recovered Africa from the Vandals (533–48) and Italy from the Ostrogoths (535–54). He was less successful in fighting the Persians and was unable to prevent the raids of the Slavs and the Bulgars. Justinian's policy of caesaropapism (i.e., the supremacy of the emperor over the church) included not only matters of organization, but also matters of dogma. In 553, seeking to reconcile the Monophysites to the church, he called a council but accomplished nothing and finally tended to drift into heresy himself. Justinian's greatest accomplishment was the codification of Roman law, commonly called the Corpus Juris Civilis Corpus Juris Civilis executed under his direction by Tribonian Tribonian (Tribonianus) It gave unity to the centralized state and greatly influenced all subsequent legal history. Justinian erected many public works, of which the church of Hagia Sophia Hagia Sophia is the most notable. He was succeeded by his nephew, Justin II. The writings of Procopius Procopius are the main source of information on Justinian's reign.