Codex Justinianus
Justinian promulgates the first Codex Justinianus
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Original prompt & settings (JSON) ↗The Code was announced on 7 April — but lawyers had to wait until the 16th before it became the only permissible source of imperial enactments.
7 April 529, by the constitution Summa
On 7 April 529 Justinian promulgated the first Codex Justinianus through the constitution Summa, addressed to the praetorian prefect Menas.
The Code gathered, edited and reconciled imperial constitutions drawn from the Gregorian, Hermogenian and Theodosian codes, together with later enactments.
Justinian’s stated reason was that the large, obscure and sometimes contradictory body of imperial constitutions prolonged litigation.
Nine days to force of law
The constitution ordered the Code distributed to the provinces, but it did not acquire force of law until 16 April 529.
A ten-member commission had reduced centuries of enactments into twelve books in about fourteen months.
Once the Code took effect, only imperial constitutions it contained could be cited; omitted constitutions and the earlier codes lost their legal force.
The book that did not survive
The first edition is lost apart from its opening constitutions and small fragments. The Codex normally read today is Justinian’s replacement edition of 534.
The commission’s chairman is disputed: some references identify John the Cappadocian, while recent scholarship argues for a different John, a former quaestor under Justin I.
Tribonian served on that commission and later led the Digest project; he was not a co-chair of it.
Sources
Researched 23 Aug 2026 5 sources not yet audited
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What the sources leave uncertain
- The date 7 April 529 is secure from Summa; 16 April, not 7 April, was the effective date.
- The 529 Code does not survive as a complete text, so its exact contents must partly be reconstructed from Summa, Haec and later references.
- The chairman's identity is disputed. Some modern references identify John the Cappadocian, while recent scholarship argues that the chairman was a different John, a former quaestor under Justin I.