In the _Etymologies_, as has been noticed, Isidore has combined the encyclopedia of education, as exemplified in the works of Martianus Capella and Cassiodorus, and the encyclopedia of the whole range of knowledge, of which the works of Varro, Pliny, and Suetonius are leading examples. The first three of the twenty books which are comprised in the _Etymologies_ are evidently educational texts; the last twelve as evidently belong to the encyclopedia of all knowledge.[152] The question is in which of these divisions the intervening books should be classed. If we look to Isidore’s predecessors for guidance on this point, we find that Capella gives only the seven liberal arts, while Cassiodorus gives not only a comprehensive account of preparatory studies in the form of the seven liberal arts, but adds in his _De Institutione Divinarum Litterarum_ a treatment of the higher, or religious, education of the monk. The supposition that Isidore followed the example of Cassiodorus is the more natural one. Their educational purpose was much the same: Cassiodorus had in mind the training of the monk, while Isidore was concerned with the education of the priest. It is, all things considered, more natural to suppose that Isidore is giving in Books I-VIII of his _Etymologies_ a comprehensive survey of the education of the secular clergy, than to suppose that his educational texts stopped short at the end of the seven liberal arts. [152] See p. 31 for outline of contents. If this supposition is correct, the outline of this survey is as follows: Grammar (Bk. I), Rhetoric and Dialectic (Bk. II), Arithmetic, Geometry, Music, Astronomy (Bk. III), Medicine (Bk. IV), Laws and Times (Bk. V), the books and services of the church (Bk. VI), God, the angels, and the orders of the faithful (Bk. VII), the church and the different sects (Bk. VIII). The inclusion of medicine, law, and chronology, which were not in the corresponding plan of Cassiodorus,[153] meant merely an enlargement of his scheme to fit it for the slightly different purpose which Isidore had in mind. The reason for the inclusion of these subjects is the practical one: in the absence of any other educated class priests were obliged to have some slight knowledge of medicine and law, while the intricacy of the church calendar of the time made chronology a professional necessity. [153] However, Cassiodorus had in the _De Institutione Divinarum Litterarum_ a chapter entitled “On monks having the care of the infirm”. In this he urged upon them the reading of a number of medical works (those of Dioscorides, Hippocrates, Galen, Caelius Aurelianus, and “various others”. Migne, _P. L._, 70, 1146).