The Egyptians had a lyre with three strings.  The early lyre of the Greeks had four, constituting their tetrachord.  In course of some centuries lyres of seven and eight strings were employed.  And, by the expiration of a thousand years, they had advanced to their “great system” of the double octave.  Through all which changes there of course arose a greater heterogeneity of melody.  Simultaneously there came into use the different modes—­Dorian, Ionian, Phrygian, AEolian, and Lydian—­answering to our keys; and of these there were ultimately fifteen.  As yet, however, there was but little heterogeneity in the time of their music.

Instrumental music during this period being merely the accompaniment of vocal music, and vocal music being completely subordinated to words, the singer being also the poet, chanting his own compositions and making the lengths of his notes agree with the feet of his verses,—­there unavoidably arose a tiresome uniformity of measure, which, as Dr. Burney says, “no resources of melody could disguise.”  Lacking the complex rhythm obtained by our equal bars and unequal notes the only rhythm was that produced by the quantity of the syllables and was of necessity comparatively monotonous.  And further, it may be observed that the chant thus resulting, being like recitative, was much less clearly differentiated from ordinary speech than is our modern song.

Nevertheless, in virtue of the extended range of notes in use, the variety of modes, the occasional variations of time consequent on changes of metre, and the multiplication of instruments, music had, towards the close of Greek civilisation, attained to considerable heterogeneity—­not indeed as compared with our music, but as compared with that which preceded it.  As yet, however, there existed nothing but melody:  harmony was unknown.  It was not until Christian church-music had reached some development, that music in parts was evolved; and then it came into existence through a very unobtrusive differentiation.  Difficult as it may be to conceive a priori how the advance from melody to harmony could take place without a sudden leap, it is none the less true that it did so.  The circumstance which prepared the way for it was the employment of two choirs singing alternately the same air.  Afterwards it became the practice—­very possibly first suggested by a mistake—­for the second choir to commence before the first had ceased; thus producing a fugue.

With the simple airs then in use, a partially harmonious fugue might not improbably thus result:  and a very partially harmonious fugue satisfied the ears of that age, as we know from still preserved examples.  The idea having once been given, the composing of airs productive of fugal harmony would naturally grow up; as in some way it did grow up out of this alternate choir-singing.  And from the fugue to concerted music of two, three, four, and more parts, the transition was easy.  Without pointing out