Roman emperor and jurist, born in Illyria; became co-emperor with Justin I. in 527; married the infamous Theodora, and for 38 years enjoyed a reign, the most brilliant of the late Empire, but not without dangers from foes outside and factions within; his fame rests on the codification and reform of the laws which he carried out; he improved the status of slaves, revised the laws of divorce and of intestate succession; and in his "Digest," "Institutes," and other sections of the "Corpus Juris Civilis," first gave definiteness to Roman law and laid the basis of the civil law of most modern nations (482-565).