Immediately after his accession, Justinian appointed a com mission to deal with the imperial constitutions (ins novum), this being the easier part of the problem. The commissioners, ten in number, were directed to go through all the constitutions of which copies existed, to select such as were of practical value, to cut these down by retrenching all unnecessary matter, and gather them, arranged in order of date, into one volume, getting rid of any contradictions by omitting one or other of the conflicting passages'. These law commissioners completed their task in four teen months, distributing the constitutions which they "retained" into ten books, in general conformity with the order of the Per petual Edict enacted by Hadrian. By this means the bulk of the statute law was immensely reduced, its obscurities and internal discrepancies in great measure removed, its provisions adapted, by the abrogation of what was obsolete, to the circumstances of Justinian's own time. This Codex constitutionum was formally for an account of the instructions given to the commission, the constitution Haec quae, prefixed to the revised Codex in the Corpus iuris civilis.
promulgated in 529, all imperial ordinances not included in it being repealed at one stroke.
The success of this first experiment encouraged the emperor to attempt the more difficult enterprise of simplifying and digest ing the old law. Before entering on this, however, he wisely took the preliminary step of settling the more important of the legal questions as to which the older jurists had been divided in opinion. This was accomplished by a series of constitutions known as the "Fifty Decisions" (Quinquaginta decisiones), along with which there were published other ordinances amending the law in a variety of points, in which old and now inconvenient rules had been suffered to subsist. Then in December 53o a new commission was appointed, consisting of sixteen eminent lawyers, under the presidency of the famous Tribonian, who had already served on the previous commission. They were to procure and peruse all the writings of all the authorized jurists (those who had enjoyed the ius respondendi); were to extract from these writings what ever was of the most permanent and substantial value, with power to change the expressions of the author wherever conciseness or clearness would be thereby promoted, or wherever such a change was needed in order to adapt his language to the condition of the law as it stood in Justinian's time; were to avoid repetitions and contradictions by giving only one statement of the law upon each point ; were to insert nothing at variance with any provision con tained in the Codex constitutionurn; and were to distribute the results of their labours into fifty books, subdividing each book into titles, and following the order of the Perpetual Edict'.
The commissioners presented their selection of extracts to the emperor in 533, and he published it as an imperial statute on December i6th of that year, with two prefatory constitutions (those known as Omnem reipublicae and Dedit nobis). It is the Latin volume which we now call the Digest (Digesta) or Pandects (116.voecrac). The extracts comprised in it are 9,123 in number, taken from thirty-nine authors, and are of greatly varying length, mostly only a few lines long. The worst thing about the Digest is its highly unscientific arrangement. The order of the Perpetual Edict, which appears to have been taken as a sort of model for the general scheme of books and titles, was doubtless convenient to the Roman lawyers from their familiarity with it, but was in itself rather accidental and historical than logical. The disposi tion of the extracts inside each title was still less rational; it has been shown by a modern jurist to have been the result of the way in which the committees of the commissioners worked through the books they had to peruse. In enacting the Digest as a law book, Justinian repealed all the other law contained in the treatises of the jurists (that ius vetus which has been already mentioned), and directed that those treatises should never be cited in future even by way of illustration ; and he of course at the same time abrogated all the older statutes which had formed a part of the ius vetus. This was a necessary incident of his scheme of reform. But he went too far, and indeed attempted what was impossible, when he forbade all commentaries upon the Digest. He was obliged to allow a Greek translation to be made of it, but directed this translation to be exactly literal.
These two great enterprises had substantially despatched Jus tinian's work; however, he, or rather Tribonian, conceived that an outline of the elementary manual law was needed to take the place of the now obsolete Cornmentarii of Gaius. The result was the publication, shortly before the Digest, of the Institutes of Justinian, a work which nevertheless, both in matter and style, owes much to the work of Gaius.
In the four years and a half which elapsed between the pub lication of the Codex and that of the Digest, many important changes had been made in the law, notably by the publication of the "Fifty Decisions." It was therefore natural that the idea should present itself of revising the Codex, so as to contain in one volume the whole Statute Law. Accordingly, another com mission was appointed, consisting of Tribonian with four other coadjutors, full power being given them not only to incorporate the new constitutions with the Codex and make in it the requisite changes, but also to revise the Codex generally. This work was the Constitution Deo author (Cod. i. 17, 1).