Soul music can find its roots in 4 different sources: racial, geographical, historical and economical. The 1950s recordings of Sam Cooke, Ray Charles and James Brown are commonly considered the beginnings of soul music. There are many different types of Soul music, including, but not limited to: Southern Soul, Neo-Soul and Psychedelic Soul (which paved the way for Funk music in the 1960s. Soul music was born in Memphis and more widely in the southern US where most of the performing artists were from.
More than any other genre of popular American music, Soul is the result of the combination and merging of previous styles and substyles in the 1950s and 60s. Broadly speaking, soul comes from a gospel (the sacred) and blues (the profane). Blues was mainly a musical style that praised the fleshly desire whereas gospel was more oriented toward spiritual inspiration.
Once it gained popularity, Soul gradually came into white musical groups and was then called "Blue-Eyed Soul." Soul music ruled the black musical charts throughout the 1960s and inspired many other music styles such as current pop music and funk. In fact it never went away, it simply evolved.