Blues

I have been playing the blues for a long time for some reason the 1 5 7 is a standard and everybody plays it. From  lead zeppelins whole Lotta love to the milk cow blues by George Strait. Every singer and band at one time or the other does some rendition of the blues Muddy Waters Jimi Hendricks Steve Ray Vaughn . So what is the deal is it the simplicity of it the three chords or is it that the lead does not have to follow the melody. So the guitar or what ever lead you have is free to just soar with out regard for the Vocal melody or structure of the song.As long as it stays with in the three chords and turn around. So it has a wide open door as far as being able to express ones self and put your style and personality on a song with out having to come up with a chord arrangement that is your own. It is build in  of course there are no new chord arrangements any more every combination has been played and put in to thousands of songs. But the blues is special in that you can play it real slow to real fast and it still holds up and  can become a great song a hundred years ago and people are wighting great songs even today. So what is it. Does it come from the slaves of the last century  in the American south or is it of Celtic origins from Ireland and the blacks just  heard there masters playing this style on there stringed instruments and slow bluegrass is just the blues that high lonesome sound from the mountains of the south. So to say the blues and jazz are American music styles is a little misleading because most of it comes from France in New Orleans and folk music from Ireland and England and Germany yes the immigrants brought this music with them and when you mix it all together Jazz Blues Country Western and Rock and Roll and even Hip Hop and Rap is what it has turned in to. And I believe these melody's are as old as the plains of Africa and the Ice Age in Europe. And that my friend is why this music hits people so deep. Just my opinion.......Enjoy the music.....