But when Dante begins the exposition of this ode it is “the sail of reason” that bears him on.

In the preamble to the Convivio Dante suggests reform in his declaring the vernacular suitable for ethical subjects as well as amorous ones. He was a leader in considering the vernacular a potential medium for all forms of expression, and his impassioned defense and praise of it manifest his awareness of its value in scientific interpretation as he comments at length on its uses.

He tells his reader that writings should be expounded in four senses. The first is the literal level. The second is the allegorical; for example, when Ovid tells his reader that Orpheus moved both animals and stones with his music he is signifying the power of eloquence over what is not rational. In this case the literal level of the story or poem need not be true. If it is not true, it is known as the allegory of poets; if the literal level is taken to be the truth, it is known as the allegory of theologians, because the literal level of the Scriptures was considered to be true. The third is the moral level, and this has a didactic purpose: when Christ took only three of his disciples with him on the occasion of the Transfiguration, it was another way of saying that for those things that are most secret we should have little company. The fourth sense is the anagogical, as when Scripture signifies certain spiritual or mystical truths. When we read, for example, that the people of Israel came out of Egypt and that Judea was made free, we must take this to be literally true, but the statement also signifies the spiritual truth that when a soul turns away from sin it becomes holy and free.

The literal level of a writing must always be exposed first, for it is impossible to delve into the “form” of anything without first preparing the “subject” upon which the form is to be stamped—you must prepare the wood before you build the table. Dante, in book II, chapter I of the Convivio, proposes to expound the literal level of his canzone first and then the allegorical, bringing into play the other levels or senses when it seems appropriate. There are very few passages in Dante’s work where all four senses are at work; in fact, of the three canzoni expounded in the Convivio he manages to treat only the first two poems on two levels, while the third he discusses only on the literal level. And when Dante talks about the literal sense he means, of course, not the words but what the words mean. We must bear in mind that the literal sense contains all the other meanings.

In the third book Dante expounds the canzone “Amor che ne la mente mi ragiona” (“Love that converses with me in my mind”), which Casella in the Divine Comedy will sing to the newly arrived souls on the shores of Purgatory. In discussing the literal level of this ode he gives most of his attention to the meaning of amor (love).

Dante begins the fourth book, which treats the third and final canzone, “ Le dolci rime d’amor ch’i’solìa “ (“Those sweet rhymes of love that I was wont”), by stressing the fact that. his love of philosophy has led him to love all those who pursue the truth and despise those who follow error. He also tells us in chapter 1 of this book that in order to have the utmost clarity he will discuss the poem only on the literal level. The lady involved, however, is still Philosophy.

Critics have proposed a number of theories on why Dante completed only four of the projected fourteen books of the Convivio. Thomas Bergin goes as far as to suggest that the Convivio might be thought of as the selva oscura (dark wood) of the Divine Comedy, from which the poet’s lady, Beatrice, in a more graceful and harmonious work of art, felt obliged to rescue her poet-lover. I tend to agree with Rocco Montano, who suspects that it was some kind of personal crisis or “conversion” that made Dante stop working on this project. Montano assigns such a conversion and the writing of the Divine Comedy to the insight that resulted from Dante the poet’s great disappointment at the failure of Henry VII’s expedition into Italy. In any case, whatever Dante’s reason for cutting short his work on the Convivio, whether it was personal or political, if this meant he could get on with the Divine Comedy and complete his masterpiece, we should be grateful that he did.

In all his works Dante shows his concern for words and the structure of language. In chapter XXV of the Vita nuova he takes time to explain and illustrate the use of personification, as he does in the early chapters of the Convivio, where he defends the use of Italian rather than Latin. But this concern is most evident in his Latin treatise De vulgari eloquentia. Before it there was no such scholarly treatment of a language. Dante completed only the first and second books, but he refers to a fourth; it is not known if that one was to be the last.

In book I Dante deals with the origin and history of the Italian language. The first five chapters cover the basic definitions of human speech while a good deal of the rest is given over to a discussion of dialects and the principles of poetic composition in the vulgar tongue, which he calls the “illustrious” vulgar tongue—the language of Guido Guinizzelli and, most perfectly, of Guido Cavalcanti, Cino da Pistoia, and Dante himself.

The second book of the De vulgari eloquentia is devoted to a more thorough discussion of Italian, which, Dante asserts, is just as appropriate for works of prose as for poetry. Early in this book (chapter II) he discusses what kind of subject is worthy of this vernacular and concludes that it is suited for only the most elevated subjects. And they are three: war (or prowess of arms), love, and virtue (or direction of the will). He states that the greatest writers using a vulgar tongue wrote only on these three subjects. Among Provencal poets, Dante cites Bertran de Born, who wrote about war, Arnaut Daniel on love, and Guiraut de Bornelh on virtue; he also mentions that in Italian Cino da Pistoia wrote about love and “his friend” (Dante), about virtue, citing an example of verse from each poet and including one of his own.