Theoretically, we have the most minute knowledge of the scientific aspect of music, dating from more than five hundred years before the Christian era. This knowledge, however, is worse than valueless, for it is misleading. For instance, it would be a very difficult thing for posterity to form any idea as to what our music was like if all the actual music in the world at the present time were destroyed, and only certain scientific works such as that of Helmholtz on acoustics and a few theoretical treatises on harmony, form, counterpoint and fugue were saved. From Helmholtz's analysis of sounds one would get the idea that the so-called tempered scale of our pianos caused thirds and sixths to sound discordantly. From the books on harmony one would gather that consecutive fifths and octaves and a number of other things were never indulged in by composers, and to cap the climax one would naturally accept the harmony exercises contained in the books as being the very acme of what we loved best in music. Thus we see that any investigation into the music of antiquity must be more or less conjectural. Let us begin with the music of the Egyptians. The oldest existing musical instrument of which we have any knowledge is an Egyptian lyre to be found in the Berlin Royal Museum. It is about four thousand years old, dating from the period just before the expulsion of the Hyksos or "Shepherd" kings. At that time (the beginning of the eighteenth dynasty, 1500-2000 B.C.) Egypt was just recovering from her five hundred years of bondage, and music must already have reached a wonderful state of development. In wall paintings of the eighteenth dynasty we see flutes, double flutes, and harps of all sizes, from the small one carried in the hand, to the great harps, almost seven feet high, with twenty-one strings; the never-failing sistrum (a kind of rattle); kitharas, the ancestors of our modern guitars; lutes and lyres, the very first in the line of instruments culminating in the modern piano. One hesitates to class the trumpets of the Egyptians in the same category, for they were war instruments, the tone of which was probably always forced, for Herodotus says that they sounded like the braying of a donkey. The fact that the cheeks of the trumpeter were reinforced with leather straps would further indicate that the instruments were used only for loud signalling. According to the mural paintings and sculptures in the tombs of the Egyptians, all these instruments were played together, and accompanied the voice. It has long been maintained that harmony was unknown to the ancients because of the mathematical measurement of sounds. This might be plausible for strings, but pipes could be cut to any size. The positions of the hands of the executants on the harps and lyres, as well as the use of short and long pipes, make it appear probable that something of what we call harmony was known to the Egyptians.