The Schiller Boston Community Chorus is an interracial vocal group “committed to performing African-American spirituals in keeping with the tradition of Hall Johnson, H.T. Burleigh, and other Black composers.” This concert, their first in Rhode Island, is part of a four-day conference marking the 400th anniversary of slavery in America. The other events are mostly sold out already, though tickets are currently still available for a Thursday event in Bristol about Rhode Island’s gradual move away from slavery. That one’s being held at Linden Place, once home to James DeWolf, the nation’s most prolific slave trader. The concert, and the conference, were organized by Stages of Freedom.