Justinian I (/dʒʌˈstɪniən/; Latin: Flavius Petrus Sabbatius Iustinianus Augustus, Greek: Φλάβιος Πέτρος Σαββάτιος Ἰουστινιανός Flávios Pétros Sabbátios Ioustinianós) (c. 482 – 14 November 565), traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church, was a Byzantine (East Roman) 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.