[115] _Musica ficta_ is music in which the ecclesiastical modes, theoretically never to be altered, are freely varied by chromatics, that is to say, in which the diatonic or natural notes of the modes are raised and lowered by sharps and flats, either to enrich the harmony or to facilitate the _leading_ of the voice parts. The instinct so to alter notes that they may glide or lead, so to speak, into certain chords is almost fundamental. The same instinct was equally powerful in another direction in forming scales even among semi-civilized races, only in scales, which are _melodic_ formulæ, the instinct is to glide downward to a final note, as, for instance, in the Dorian tetrachord of the Greeks, whereas in harmonic music the instinct is to glide upward. The so-called _leading tone_ in our scale is the result of harmonic instinct, and its final establishment in the scale is certainly heralded in _musica ficta_. A comparison of the so-called natural and harmonic minor scales in our own system will, perhaps, make the matter clear to the reader lacking technical knowledge. The natural A-minor scale comprises on the keyboard the white notes from A to a. In the harmonic minor, that is to say, in the minor scale so altered as to be suitable for the purposes of harmony, the G is raised a half tone by a sharp and therefore _leads_ irresistibly to the A above it. This sharping of the G augments the natural interval from F to G, and, since this augmented interval is hard to sing, the F, too, is sometimes sharped, and the scale then becomes what we call the melodic minor. Nothing could be more indicative than this 'melodic’ compromise of the power harmony has exercised over the development of music, for rather than do without the _leading_ tone, which is itself an alteration of the natural scale, we alter the scale still further. Our melodic minor scale is therefore constructed to square with the harmonic need, a queer paradox. Before harmony came to influence composers the true melodic alteration of this scale of white notes between A and a would have been the flatting or lowering of the B, so that the melody might attain its most natural end on the lowest note of the scale by a gliding half-step. It should be noted that relatively few indications of chromatic alterations in _musica ficta_ were written in the score. Singers were given a special training to enable them to recognize when such alterations were necessary, and to alter correctly. Thus in connection with _musica ficta_ elaborate rules were formulated which are not distantly removed from our own rules of harmony. [116] _Cf._ Chap. IX, p. 275. [117] Born 1517 at Chioggia, in Venetia; died 1590 at Venice. [118] _Cf._ Chap. IX, p. 274. [119] Also called Orlandus de Lassus. [120] This work contains the portrait which we reproduce herewith, and which, taken in connection with its setting and the history of the man, is of uncommon interest.