Minor scale based on the accidentals of the "natural" minor scale, not on those of the harmonic or melodic minor scales. For example, a piece in E minor will have one sharp in its key signature because the E natural minor scale has one sharp (F). Major and minor keys that share the same key signature are "relative" to each other. For instance, F major is the relative major of D minor since both have key signatures with one flat. Since the natural minor scale is built on the 6th degree of the major scale, the tonic of the relative minor is
Music of Mesopotamia same key signature as a C-major scale. The F-Major scale has a B-flat in the key signature, however with the raised fourth in the lydian scale, the B-flat becomes a B-natural. The drawback in modern music with the lydian scale is the use of what's known today as the "devil's tritone," however, the Mesopotamians don't seem to have a term for this interval, nor a term for the octave which we know they had a concept of. The use of a heptatonic scale would have eliminated any practical need for a term for the octave, as it wouldn't have the