Codification of Roman Law
Justinian's most enduring achievement was the Corpus Juris Civilis, a comprehensive revision of Roman law produced under the direction of the jurist Tribonian. It comprised the Codex Justinianeus, the Digesta, the Institutiones, and the later Novellae. The first draft of the Codex appeared on 7 April 529, the Digesta followed in 533, and the final version of the Codex was issued in 534.
These reforms laid foundations of civil law still drawn upon worldwide. Notable provisions included restrictions on divorce, protections for prostitutes and for women, improved rights for children, protections for slaves, and measures restricting non-Christians from holding public office. The Church laws contained in the codex were later incorporated into Russian canonical collections.
Building Works
After the church of Hagia Sophia in Constantinople was destroyed during the Nika riots of January 532, Justinian rebuilt it on a grand scale under the architects Isidore of Miletus and Anthemius of Tralles. The new church was completed on 26 December 537 at a reported cost of 20,000 pounds of gold and was reinaugurated on 24 December 562. According to tradition, Justinian declared at its completion, 'Solomon, I have outdone thee.'
His patronage extended across the empire. Other structures associated with his reign include San Vitale in Ravenna, the Church of the Holy Apostles, the Little Hagia Sophia, Saint Catherine's Monastery at Sinai, the Church of the Nativity, Hagia Irene, the Basilica Cistern, the Dara Dam, the Sangarius Bridge, and the new city of Justiniana Prima near his birthplace. Orthodox tradition records that he ordered the construction of about ninety churches for newly converted populations and funded many churches dedicated to the Theotokos.
Defense of Orthodoxy
A Chalcedonian Christian, Justinian sought religious unity by enforcing Orthodox doctrine throughout the empire. He promulgated laws affirming belief in the Holy Trinity and the Incarnation and established the Nicene-Constantinopolitan Creed as the Church's sole symbol of faith. He actively combated Origenist and Nestorian teaching and convened the Fifth Ecumenical Council in 553 to condemn the teachings of Origen and the Three Chapters and to affirm the definitions of Chalcedon.
He placed the Neoplatonic Academy in Athens under state control in 529, effectively ending pagan philosophical training, and abolished pagan worship sites, including temples dedicated to Ammon and Isis. He sponsored Christian missionary activity: John, Bishop of Ephesus, was sent to evangelize Asia Minor, where he is said to have baptized more than 70,000 pagans. Justinian promoted the concept of 'symphony' between church and state and emphasized clerical education in rhetoric, philosophy, and theology; his legal codes protected ecclesiastical property, defined clerical rights, and regulated monastic life. He himself authored theological treatises and is described on the Orthodox calendar as a great champion of Orthodoxy.
Liturgical Contributions and Personal Piety
Orthodox tradition credits Justinian with standardizing the Divine Liturgy and introducing the Cherubic Hymn. The hymn 'Only-Begotten Son and Immortal Word of God,' composed at his command, remains sung at the Divine Liturgy, and the hymn 'O Gladsome Light' is also traditionally attributed to him.
He is remembered for rigorous personal asceticism, fasting strictly during Great Lent and consuming only water and vegetables. His intensity of work earned him the description 'the emperor who never sleeps.'
Military Reconquests
Under Justinian, Byzantine armies recovered large parts of the former Western Roman Empire. The general Belisarius conquered the Vandal Kingdom in North Africa in 533–534, recovering Carthage, Sardinia, Corsica, and the Balearic Islands. Italy was recovered from the Ostrogoths in a prolonged campaign (535–554), and the general Narses defeated the Ostrogoths at Busta Gallorum in 552.
Wars with Persia were fought in 527–532 and 540–562, concluding in a fifty-year peace in 562 that required annual Byzantine payments. In 552 Justinian sent forces to Hispania, establishing the province of Spania. These victories contributed to the suppression of paganism among Germanic peoples, including the Vandals and Visigoths.
Crises of the Reign
The Nika riots of January 532 nearly toppled Justinian's reign. Though the emperor considered fleeing, he remained after Empress Theodora refused to leave, and the uprising was suppressed by the generals Belisarius and Mundus; an estimated 30,000 unarmed civilians died.
In 541–543 the empire was devastated by the plague that bears his name, the Plague of Justinian; the emperor himself contracted and recovered from it. Extreme weather in 535–536, thought to have been volcanic in origin, produced famine across Europe and the Middle East.
Contested Theological Legacy
Some sources suggest that late in life Justinian may have inclined toward Aphthartodocetism, a view holding the body of Christ to be incorruptible, which is said to have led to the deposition of Patriarch Eutychius. Contemporary scholars debate this account, with some arguing that the evidence is insufficient.
The position for which the Orthodox Church venerates him, and his official stance, was firmly Chalcedonian Orthodox.