De institutione musica I.20: De additionibus chordarum earumque nominibus.
Nicomachus reports that music was at the beginning so simple that it consisted of four strings, and this lasted down to Orpheus, so that the first string and the fourth sounded the diapason consonance, and the middle ones to each other and to the extremes the diapente and diatessaron, while nothing in them was dissonant, in imitation, that is, of the music of the world, which consists of four elements. Mercury is said to be the inventor of this four-stringed lyre. A fifth string was added afterwards by Coroebus, son of Atys, who was king of the Lydians. Hyagnis the Phrygian added a sixth string to these. But the seventh string was added by Terpander of Lesbos, in likeness, namely, to the seven planets. Of these, the lowest was called hypate, as the greater and more honourable, whence they also call Jupiter hypatos. They name the consul also by the same name, on account of the excellence of his dignity. And it was assigned to Saturn, on account of the slowness of his motion and the lowness of the sound. The second is parhypate, as if placed and set beside the hypate. The third is lichanos, because lichanos is the name of the finger that we call the index finger. The Greek calls it lichanos from licking. And since in singing, at the string that was third from the hypate, the index finger, which is lichanos, was found, that string too was called lichanos. The fourth is called mese, since among the seven it is always the middle. The fifth is paramese, as if placed beside the middle. The seventh is called nete, as if neate, that is, lowest; and the sixth, which is between this nete and the paramese, is called paranete, as if placed beside the nete. The paramese, since it is third from the nete, is also called by the same name trite, so that the description is this:
To these Lycaon of Samos added an eighth, and fitted a string in the middle between the paramese, which is also called trite, and the paranete, so that it was itself third from the nete; and the paramese alone was called by that name, which was placed after the middle. The trite lost its name after the string was placed between it and the paranete, third from the nete, which worthily received the name trite; so that the octachord, according to Lycaon’s addition, is this:
In the two foregoing arrangements, then, of the heptachord and the octachord, the heptachord is called synemmenon, which means conjoined, but the octachord diezeugmenon, which means disjoined. For in the heptachord there is one tetrachord: hypate, parhypate, lichanos, mese; the other is mese, paramese, paranete, nete, since we count the mese string a second time. And therefore the two tetrachords are joined through the mese. In the octachord, however, since there are eight strings, the upper four, that is hypate, parhypate, lichanos, mese, fill out one tetrachord. From this the other, disjoined and complete, begins at the paramese and proceeds through the trite and the paranete and ends at the nete. And the disjunction is what is called diazeuxis, and the distance of the mese and the paramese is a tone. Here, then, the mese keeps the name only. It is not in a middle position, because in an octachord two middle strings are always found, but one middle cannot be found. Prophrastus of Pieria added one string to the lower part, to make a complete nine-stringed instrument. Since it was added above the hypate, it was named hyperhypate. This, when the cithara had only nine strings, was formerly called hyperhypate. Now, however, with others added above it, it is called lichanos hypaton, and in this order and arrangement, since it comes to the index finger, it is called lichanos. But this will appear later; now the order of the nine-stringed instrument stands thus:
Histiaeus of Colophon fitted a tenth string to the lower part, and Timotheus of Miletus an eleventh; since these were added above the hypate and parhypate, they were called hypate hypaton, as the greatest of the great, or the lowest of the low, or the excellent of the excellent. The first of the eleven was called hypate hypaton, the second parhypate hypaton, since it is placed next to the hypate hypaton. The third, which was formerly in the nine-stringed instrument called hyperhypate, was named lichanos hypaton. The fourth kept the old name hypate, the fifth parhypate, the sixth lichanos, having its old name, the seventh mese, the eighth paramese, the ninth trite, the tenth paranete, the eleventh nete. There is, then, one tetrachord: hypate hypaton, parhypate hypaton, lichanos hypaton, hypate; another is hypate, parhypate, lichanos, mese. And these are conjoined. The third is paramese, trite, paranete, nete. But since between the upper tetrachord, which is hypate hypaton, parhypate hypaton, lichanos hypaton, hypate, and the lowest, which is paramese, trite, paranete, nete, there is in position a middle tetrachord, which is hypate, parhypate, lichanos, mese, this whole middle tetrachord was called meson, as of the middle ones, and is named with this addition: hypate meson, parhypate meson, lichanos meson, mese. And since between this meson tetrachord and the lower, which is that of the netai, there is a disjunction, namely of the mese and the paramese, the whole lower tetrachord was called diezeugmenon, of the disjoined, with this addition: paramese diezeugmenon, trite diezeugmenon, paranete diezeugmenon, nete diezeugmenon, so that the description is in this manner:
There is, then, here a disjunction between the paramese and the mese, and therefore this tetrachord is called diezeugmenon. But if the paramese is taken away, and there are mese, trite, paranete, nete, then the three tetrachords will be conjoined, that is, synemmena, and the last tetrachord will be called synemmenon, in this manner:
But since in this arrangement, or the foregoing, of the eleven strings, the mese, which was so named from its middle position, comes nearest to the nete and stands far from the last of the hypatai and does not keep its proper place, one more tetrachord was added above the nete diezeugmenon; and since these surpassed in high pitch the netai placed above, that whole tetrachord was called hyperboleon, in this manner:
But since again the mese was not in the middle in place but approached rather the hypatai, one string was added above the hypatai hypaton, which is called proslambanomenos (by some it is called prosmelodos), distant a whole tone from the one that is hypate hypaton. And this one, the proslambanomenos, is the eighth from the mese, sounding with it the diapason symphony. The same sounds the diatessaron with the lichanos hypaton, being the fourth to it; and the lichanos hypaton sounds with the mese the diapente symphony, and is the fifth from it. Again, the mese is distant a tone from the paramese, and the same mese makes with the nete diezeugmenon the fifth, a diapente consonance. The nete diezeugmenon makes with the nete hyperboleon the fourth, a diatessaron consonance. And the proslambanomenos gives with the nete hyperboleon the double diapason consonance.