The Oxford History of Western Music, Pt. 2

More fun facts.

• Melismatic melodic turns helped group and identify chants together, and acted in a similar way to the term mode as defined in it's earliest usages
• Our concept of a mode, more closely related to the final note of a melody, has less in common with Gregorian chant, and is a product of Frankish and Italian music theorists in the tenth century, when they made efforts to categorise the music of the Roman church according to ancient Greek music theory.
• The harmonic series, often used to show that "naturalness" of the diatonic scale, was actually only discovered in the eighteenth century. According to one fable, Pythagoras passed by a blacksmith shop, heard pitches, and used the weights of the anvils to determine the pitches, which corresponded to the intervals of the perfect 4th, perfect 5th, and tone. Transposing this same pitch set (0, 5, 7) to begin on the any other those notes gives rise to the pentatonic scale.