This work is lost. It was an encyclopedia in at least ten books, of which the titles of some books and fragments have been recovered, a large portion of them from the _Etymologies_ and _De Natura Rerum_. Among the subjects were _leges_, _mores_, _tempora_, _mundus_, _animantium naturae_. Isidore quotes Suetonius twice. See A. Reifferscheid, _C. Suetoni Tranquilli Reliquiae_, Leipzig, 1860, pp. 155 _et seq._, and Schanz, _Geschichte der Römischen Literatur_, Dritter Teil, pp. 47–66. Nonius Marcellus (early fourth century). _Compendiosa Doctrina ad Filium._ Bks. 1–12. Grammatical in character, including one book, (5) _De Differentia Similium Significationum_. 13. de genere navigiorum. 14. de genere vestimentorum. 15. de genere vasorum vel poculorum. 16. de genere calciamentorum. 17. de coloribus vestimentorum. 18. de genere ciborum vel potorum. 19. de genere armorum. 20. de propinquitatum vocabulis. This work is, in part, in dictionary form (Bks. 1–6). There is much resemblance between passages in Nonius Marcellus and in the _Etymologies_, which Nettleship believes to be due to the use of a common source. Nettleship, “Nonius Marcellus,” in _Lectures and Essays_. Lindsay, _Nonius Marcellus_, Oxford, 1901. But though the example which was furnished by the Roman encyclopedists was by far the strongest literary factor which influenced Isidore in the composition of the _Etymologies_, it was not the only one of importance. A minor type of encyclopedia, that of education, occurs in Latin literature. The first example of it is furnished by Varro in his _Disciplinarum Libri IX_;[49] this work had, however, disappeared before Isidore’s time. Varro found no successor until the fourth century, when Martianus Capella wrote his account of the seven liberal arts,[50] giving thus a comprehensive treatment of the subject-matter of education. He was followed in the sixth century by Cassiodorus, whose _De Artibus et Disciplinis Liberalium Litterarum_ Isidore certainly had before him when he wrote the account of the seven liberal arts which occupies the first three books of the _Etymologies_. Isidore’s work therefore appears to be a fusion of the minor encyclopedia of education and the major encyclopedia of all knowledge. [49] _Disciplinarum Libri IX._ Bk. 1. Grammar. Bk. 2. Dialectic. Bk. 3. Rhetoric. Bk. 4. Geometry. Bk. 5. Arithmetic. Bk. 6. Astrology. Bk. 7. Music. Bk. 8. Medicine. Bk. 9. Architecture. (Conjectural list of disciplines given by Ritschl, _Opusc._ 3, p. 312.) [50] Martianus Capella, _De Nuptiis Philologiae et Mercurii_.