In order to set an example of literary diligence to his monks, and to be able to sympathise with the difficulties of scribe work, Cassiodorus himself transcribed (probably from the translation of Jerome) the Psalter, the Prophets, and the Epistles. In addition to his labours as a transcriber, Cassiodorus did a large amount of work as an original author and as a compiler. According to the judgment of Migne, Franz, and Hodgkin, the importance of his original writings varied very considerably, and is by no means to be estimated in proportion to their bulk. One of the most considerable of these was his great commentary on the Psalms, in the text of which he was able to discover refutations of all the heresies that had thus far racked the Church, together with the rudiments of all the sciences which had become known to the world. This was followed by a commentary on the Epistles and by a history of the Church, the latter having been undertaken in co-operation with his friend Epiphanius. This history, known as the _Historia Tripartita_, is said to have had a larger circulation than any other of the author’s works. A fourth work, which gives more of the personality of the writer, was an educational treatise entitled, _Institutiones Divinarum et Humanarum Lectionum_. In the first part of this treatise, which bore the title of _De Institutione Divinarum Litterarum_, the author gives an account of the organisation of his _scriptorium_. In the second division of the treatise, entitled _De Artibus ac Disciplinis Liberalium Litterarum_, the author states his view of the relative importance of the four liberal arts, Grammar, Rhetoric, Logic, and Mathematics, the last named of which he divides into the four “disciplines” of Arithmetic, Geometry, Music, and Astronomy. Geometry and Astronomy occupy together one page, Arithmetic and Music each two pages, Grammar two pages, Rhetoric six pages, while to Logic are devoted eighteen pages. The final production of his industrious life was a treatise called _De Orthographia_, which was completed when its author was ninety-three years old, and which was planned expressly to further the work of the monastic scribes in collecting and correcting the codices of ancient books.