Compléter The reign of JustinianVersion en ligne Byzantine empire par Susana López 1 Eastern Byzantine Constantinople Theodora Greek Visigoths trade Germanic Code Vandals Ostrogoths Justinian coins The Roman Empire survived the invasions and became known as the Empire . Its capital city , , was built over the ancient city of Byzantium . The Emperor ( 527 - 565 ) and his wife , , recaptured much of the Western Roman Empire . His armies defeated the in North Africa , the in Italy and the in southern Hispania . The economy improved thanks to and gold were introduced . Justinian unified the laws and collected them in the of Justinian .