Claim: Justinian I ruled the Byzantine Empire.

Justinian I -LRB- -LSB- dʒʌˈstɪniən -RSB- Flavius Petrus Sabbatius Iustinianus Augustus Φλάβιος Πέτρος Σαββάτιος Ἰουστινιανός Flávios Pétros Sabbátios Ioustinianós -RRB- -LRB- 482 14 November 565 -RRB- , traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church , was a Byzantine -LRB- East Roman -RRB- emperor from 527 to 565 . During his reign , Justinian sought to revive the empire 's greatness and reconquer the lost western half of the historical Roman Empire . Justinian 's rule constitutes a distinct epoch in the history of the Later Roman empire , and his reign is marked by the ambitious but only partly realized renovatio imperii , or `` restoration of the Empire '' .   Because of his restoration activities , Justinian has sometimes been called the `` last Roman '' in modern historiography . This ambition was expressed by the partial recovery of the territories of the defunct western Roman Empire . His general , Belisarius , swiftly conquered the Vandal kingdom in North Africa . Subsequently , Belisarius , Narses , and other generals conquered the Ostrogothic kingdom , restoring Dalmatia , Sicily , Italy , and Rome to the empire after more than half a century of rule by the Ostrogoths . The prefect Liberius reclaimed the south of the Iberian peninsula , establishing the province of Spania . These campaigns re-established Roman control over the western Mediterranean , increasing the Empire 's annual revenue by over a million solidi . During his reign Justinian also subdued the Tzani , a people on the east coast of the Black Sea that had never been under Roman rule before .   A still more resonant aspect of his legacy was the uniform rewriting of Roman law , the Corpus Juris Civilis , which is still the basis of civil law in many modern states . His reign also marked a blossoming of Byzantine culture , and his building program yielded such masterpieces as the church of Hagia Sophia . A devastating outbreak of bubonic plague in the early 540s marked the end of an age of splendour .