People often wonder where the “Blues” came from and how it came about. Here’s the story that makes the most sense to me. It seems a curious blending of Western and African culture.
In Western music the scales within the octave are divided by whole tones and half tones, in African music the scales are divided by whole tones, half tones and quarter tones. The end result is different levels of tension within the music. The foundation of Western harmony is the major scale. There is a similar scale in African music where the 3rd and 7th tones of the scale are a quarter tone flat. The result is the 3rd and 7th intervals of the scale aren’t major or minor intervals, they are in between. This scale is not playable on a piano or most Western instruments without the “bent” note.
Eventually some person who was brought over to America as a slave found themselves on a piano. They knew the scale they wanted to play but it wasn’t on the instrument. The closest they could come was playing a major chord in the left hand and playing a minor third in the melody with the right. The missing note still was not there, it was implied. This is the essence of the blues sound. The African 7th was implied by playing the 1st chord of the key as a Dominant 7 and not the Major 7th chord of classical harmony. This is also the essence of the blues sound. The musical style would not have occurred without the crossing of the cultures.
The first use of the word blue in describing a feeling in song lyrics happened in England in about 1720. The first time a blues was written down on staff paper happened in New Orleans in about 1910. The person who did the transcription was a Neapolitan who had been in the country about 6 weeks.