This is what we found on Wikipedia regarding the Thee Sacred Souls:

Soul music is a popular music genre that originated in the African-American community throughout the United States in the late 1950s and early 1960s. It has its roots in African-American gospel music and rhythm and blues. Soul music became popular for dancing and listening, where U.S. record labels such as Motown, Atlantic and Stax were influential during the Civil Rights Movement. Soul also became popular around the world, directly influencing rock music and the music of Africa. It also had a resurgence in the mid-to late 1990s with the subgenre neo-soul, which added modern production elements and influence from hip-hop.

Catchy rhythms, stressed by handclaps and extemporaneous body moves, are an important feature of soul music. Other characteristics are a call and response between the lead vocalist and the chorus and an especially tense vocal sound. The style also occasionally uses improvisational additions, twirls, and auxiliary sounds. Soul music reflects the African-American identity, and it stresses the importance of an African-American culture. The newfound African-American consciousness led to new styles of music that boasted pride in being black, and being such a creative genre of music, it emerged from the power struggle to increase black Americans' awareness of their African ancestry. Soul music also combines different elements of music which includes gospel music, rhythm and blues and jazz.

Soul music dominated the U.S. R&B chart in the 1960s, and many recordings crossed over into the pop charts in the U.S., Britain, and elsewhere. By 1968, the soul music genre had begun to splinter. Some soul artists developed funk music, while other singers and groups developed slicker, more sophisticated, and in some cases more politically conscious varieties. Many soul artists gained popularity due to the domination of soul music in the R&B charts. Among these artists were Ray Charles, James Brown and the soul group the Temptations. By the early 1970s, soul music had been influenced by psychedelic and progressive rock, among other genres, leading to psychedelic and progressive soul. The United States saw the development of neo soul around 1994. There are also several other subgenres and offshoots of soul music.

The key subgenres of soul include the Motown style, a more pop-friendly and rhythmic style; deep soul and southern soul, driving, energetic soul styles combining R&B with southern gospel music sounds; Memphis soul, a shimmering, sultry style; New Orleans soul, which came out of the rhythm and blues style; Chicago soul, a lighter gospel-influenced sound; Philadelphia soul, a lush orchestral sound with doo-wop-inspired vocals; and psychedelic soul, a blend of psychedelic rock and soul music.