There is probably not a reson it was created. But it started from the black slaves in the south, they would sing while working in the feilds and that then started to create what is now called the "blues"
Blues on Top of Blues was created in 1968.
Hesitation Blues was created in 1915.
Blues People was created in 1963.
Naked Blues was created in 2002.
More Blues was created in 1969.
Blues' Blues was created in 1972.
Blues on Top of Blues was created in 1968.
Your Blues was created in 2004.
About the Blues was created in 1957.
I Am the Blues was created in 1970.
Funeral Blues was created in 1936.
Sings the Blues was created on 2005-03-08.
Summertime Blues was created in 1968.
The Blues Busters was created in 1960.
Blues Incorporated was created in 1961.
Why I Sing the Blues was created in 1983.
Cardiff Blues was created in 2003.