Narratives of the great migration and the Harlem renaissance have dominated conversations around African American art in the 20th century, but a new exhibition, Souls Grown Deep Like the Rivers, which opens at the Royal Academy in London this week, invites us to consider the cultural contribution of artists from the American south. Communities that remained there in the aftermath of the civil war continued to be exposed to extremes of racial violence, segregation and the hardship of economic exclusion.