To the Most Illustrious and Excellent Prince, Lord Lodovico Maria Sforza, Duke of the Milanese, most unconquered. Franchino Gaffori, Professor of Music, sends greetings.

A decorative initial letter Q contains a floral or geometric pattern.We are easily taught by the example of the ancients, most illustrious Prince, how much the profession of the musical art stood in authority and even veneration. We see this in the example of the greatest philosophers, who, even in their old age, applied themselves to this discipline as if to set the final touch upon their studies. Furthermore, the institutes of the most severe republics, which with the greatest diligence took care to prune away whatever might publicly harm morals, nevertheless not only did not eject this art, but even cultivated it with the greatest zeal as a parent and nurturer of morals. To conclude once and for all, it is confirmed by the consenting and stable judgment of all peoples and all nations, among whom nothing was ever celebrated with greater care. For what other discipline has been received with such assent of mortals and such conspiracy of every age and sex, so that no person of any condition has yet been found who does not strive to console their troubles with at least a rudimentary melody? Nothing is proven, not only by the testimony of the best men but also by ocular (as they say) faith, to lead minds to the most diverse affections in a brief moment as effectively as music, so that antiquity did not hesitate to call its professors not only musicians but also seers and wise men. To this is added the authority of the poets, who imagined that Linus and Orpheus, born of the gods, drew trees and stones because they brought the hard and rustic life of certain men back to a milder culture. But lest perhaps little faith be placed in the words of the poets, as if they extolled everything with a figure of speech familiar to them, there have been professors of wisdom who did not hesitate to assert that not only sensible things but even those which live somehow beyond sense are soothed by musical modulations. And for this reason, some have thought that the eminent author Virgil, not out of poetic hyperbole, said to Silenus in the Bucolics that song had moved the tops of hard oaks. Indeed, if we believe Plato, who said that the soul of the world consists of musical modulation, I do not see why it should be doubted that other things also living by whatever soul—which it is clear is given to them from heaven—are not affected and gladdened by what is congruent to their nature, since it is now openly established that they are friendly by similarity. For these reasons, most illustrious Prince, with nature itself impelling me to this—a movement to which we do not easily resist—when I had applied my mind to this discipline from my early youth, which is especially conducive to morals as the most experienced agree, and is not abhorrent to my profession, and following the long-accepted opinion of religious men that this is a most important duty, namely that my studies should not profit me alone, I have published a book following the reasonings of the ancients concerning the speculation of this art, which the Greeks call Theorica Theory, so that the rationale of my studies might be established and the fruits of my labors might be scattered more widely. This work, illustrious Prince, I have dedicated to your name, albeit hesitantly and timidly, for fear that I might obstruct you, occupied as you are with the most weighty cares and the burdens of the greatest matters, with untimely trifles. But after I perceived with what favor and what kindness you followed this little work.