Gregory also founded a singing school in Rome, which was large enough to occupy two good-sized edifices. In this he probably taught personally. There have been shown as relics of his instruction, the couch on which he sat while teaching, and the rod with which the boys were corrected, or awed into giving proper attention to their studies. The amplification which he made in the Ambrosian scale was the addition of four tones or plagal modes, and also that he totally abolished the difficult Greek nomenclature, such as _para-mese_ and _proslambanomenos_, and gave the names of the first seven letters of the Roman alphabet, to the seven notes, A, B, C, D, E, F, G, in the same manner as used to-day. There is no question but that the scale founded by Gregory, had a diatonic character, but as to the number of systems of tones employed, authorities differ, and even the books of music of Gregory’s own compilation (one of which was chained to the altar at St. Peters, to fix the standard of tone for ever and ever) do not clear up the difficulty, for the number differs. But the system gradually settled itself, and eight tones only (our ordinary diatonic scale tones) were found practicable for composition and singing. Gregory’s system was founded on the division of the octave into two intervals; a perfect fifth and perfect fourth. The fifth was, next to the octave, the most important interval. The added modes (called plagal, signifying “oblique, sideways”), were so called to distinguish them from the authentic tones or keys (D, E, F, G, A), a synopsis of the entire set of tones would be as follows,— A, B, C, D, E, F, G, A, B, C, D, plagal 4, authentic 5, plagal 4. There were four authentic modes, viz.,—D, E, F and G, and four plagal, as follows,—A, B, C and D. To give a description that would be at all adequate, of the system of Gregory, would require much space, and many plates and engravings. We shall therefore touch but lightly on the tone systems and notations of the early and middle ages. The founding of the scale from a fifth and fourth, led to one grave mistake; these intervals were supposed to be of prime importance, and more perfect than others, and finally were employed in harmonies which were decidedly harsh. But to such an extent did the evil spread that no composition (in the dark ages) was thought to be pure or classic, without containing a series of fourths, fifths, and octaves, and an invariable close upon an empty fifth. Thirds were rejected as totally impure. But these faults are not of Gregory’s origination, and he must ever stand as the man who made the connecting link between the old Greek music and our own. CHAPTER XXII. MUSIC IN EUROPE FROM THE FIFTH CENTURY.