Justinian I (483-565), called The Great, Byzantine emperor (527-65), who extended Byzantine rule in the West, beautified Constantinople (present-day Istanbul), and completed the codification of Roman law. His full name was Flavius Petrus Sabgatius Justinianus. The nephew of Emperor Justin I, Justinian was born in Illyria and educated in Constantinople (now Istanbul, Turkey). In 518 he became the administrator for Justin, who named Justinian as his successor. He married Theodora, a former actress, in 523. On the death of his uncle in 527, Justinian was elected emperor.