The ancient Greeks established a system of scales as early as 600 B.C., which they named after
their most important tribes: the Dorian, Phrygian, Lydian and Mixolydian.

All of the ancient scales had the 8 notes (NOT counting the octave) which are equivalent to the white
notes on a keyboard today, and each scale descended from a different note. hmmm, interesting.

By the Middle Ages the Greek scales were still the most popular amongst composers of the day.
Eventually, in the 10th centuty, these scales were adopted by the Catholic Church

The intervals of these ancient Greek scales essentially dictated the arrangement of the modern
keyboard and it’s accidental system of black notes, both of which emerged in the 13th and
14th centuries.

Eventually, the tones of the major scale were numbered 1 through 7 and the other
tones would thereafter be referred to by their relationship to a neighboring major scale tone:

Sharp fifth, flat third, flat seventh and so on. So easy!

1st 2nd 2nd 4 3rd 4th 7 5th 9th 6th 11 7th