1. The disciplines belonging to the liberal arts are seven. First, grammar, that is, practical knowledge of speech. Second, rhetoric, which is considered especially necessary in civil causes because of the brilliancy and copiousness of its eloquence. Third, dialectic, called also logic, which separates truth from falsehood by the subtlest distinctions. 2. Fourth, arithmetic, which includes the significance and the divisions of numbers. Fifth, music, which consists of poems and songs. 3. Sixth, geometry, which embraces measurements and dimensions. Seventh, astronomy, which contains the law of the stars. Chapter 3. On the ordinary letters. 1. The foundations of the grammatic art are the ordinary letters, which elementary teachers[176] are occupied with, instruction in which is, as it were, the infancy of the grammatic art. Whence Varro calls it _litteratio_. Letters are signs of things, symbols of words, whose power is so great that without a voice they speak to us the words of the absent; for they introduce words by the eye, not by the ear. [176] _Librarii et calculatores._ 2. The use of the letters was invented in order to remember things. For things are fettered by letters in order that they may not escape through forgetfulness. For in such a variety of things all could not be learned by hearing and held in the memory. 4. Latin and Greek letters have evidently come from the Hebrew. For among the latter _aleph_ was first so named; then [judging] by the similarity of sound it was transmitted to the Greeks as _alpha_; likewise to the Latins as _a_. For the borrower fashioned the letter of the second language according to similarity of sound, so that we can know that the Hebrew language is the mother of all languages and alphabets.[177] [177] From Jerome, _ad Soph._, in Migne, _Patr. Lat._, 6, 7, 30. 7. The letter Υ Pythagoras of Samos first made, after the model of human life, whose lower stem denotes the first of life, which is unsettled and has not yet devoted itself to the vices or the virtues. The double part which is above, begins in youth; of which the right side is steep, but leads to the blessed life; the left is easier, but leads down to ruin and destruction.... 8. Among the Greeks there are five mystic letters.[178] The first is Υ, which denotes human life, of which we have just spoken. The second is Θ, which denotes death. For judges used to place this letter, theta, at the names of those whom they condemned to death; and it is called theta ἀπὸ τοῦ θανάτου, _i.e._, from death. Whence also it has a weapon through its middle, _i.e._, the sign of death. Of which a certain one speaks thus: O multum ante alias infelix littera theta! [178] This sentence, as many others, is in the accusative and infinitive without any governing verb.