Dante encounters the soul of the emperor Justinian in the heavenly sphere of Mercury. Justinian was the emperor of the Roman Empire, based at Constantinople, in the sixth century C.E. Though he had military triumphs under his general, Belisarius, Justinian is best known for undertaking a comprehensive codification of Roman law, which was subsequently received as the basis for law in Europe. Because Justinian successfully held together the fragmenting Empire in his own day, Dante sees him as a symbol of hope for the restoration of the Holy Roman Empire in his day. For Dante, the justice practiced in the Roman Empire is an earthly counterpart to divine justice.