The _Brachylogus_, as a book of Institutes, compares favourably with its model, from the language of which it departed at will. Both works are divided into four _libri_; but the _libri_ of the _Brachylogus_ correspond better to the logical divisions of the law. Again, frequently the author of the _Brachylogus_ breaks up the chapters of Justinian’s _Institutes_ and gives the subject-matter under more pertinent headings. Sometimes the statements of the older work are improved by rearrangement. The definitions of the _Brachylogus_ are pithy and concise, even to a fault. Often the exposition is well adapted to the purposes of an elementary text-book,[384] which was meant to be supplemented by oral instruction. On the whole, the work shows that the author is no longer encumbered by the mass or by the advanced character of his sources. He restates their substance intelligently, and thinks for himself. He is no compiler, and his work has reached the rank of a treatise. The merits of the _Brachylogus_ as an elementary text-book are surpassed by those of the so-called _Summa Codicis Irnerii_, a book which may mark the beginning of the Bologna school of law, and may even be the composition of its founder. Many arguments are adduced for this authorship.[385] The book has otherwise been deemed a production of the last days of the school of law at Rome just before the school was broken up by some catastrophe as to which there is little information. In that case the work would belong to the closing years of the eleventh century, whereas the authorship of Irnerius would bring it to the beginning of the twelfth. At all events, its lucid jurisprudential reasoning precludes the likelihood of an earlier origin. This _Summa_ is an exposition of Roman law, following the arrangement and titles of Justinian’s _Codex_, but making extensive use of the _Digest_. It thus contains Roman jurisprudential law, and may be regarded as a compendious text-book for law students, forming apparently the basis of a course of lectures which treated the topics more at length.[386] The author’s command of his material is admirable, and his presentation masterly. Whether he was Irnerius or some one else, he was a great teacher. His work may be also called academic, in that his standpoint is always that of the Justinianean law, although he limits his exposition to those topics which had living interest for the twelfth century. Private substantial law forms the chief matter, but procedure is set forth and penal law touched upon. The author appreciates the historical development of the Roman law and the character of its various sources--praetorian law, _constitutiones principum_, and _responsa prudentium_. He also shows independence, and a regard for legal reasoning and the demands of justice. While he sets forth the _jus civile_, his exposition and approval follow the dictates of the _jus naturale_.