Alvin Ailey, an American dancer and choreographer, is seen as one of leading modern dance artists of the mid-to-late twentieth century. His company, the Alvin Ailey Dance Theatre, was the first black dance company to travel abroad, and he was regarded as a great ambassador for black American modern dance throughout the world. His most famous work, Revelations, is based on black culture in America and is filled with emotion. The movements, music, and costumes used in Revelations have made it a signature piece for the company. In addition to black themes, Ailey has choreographed many pieces with various subject matters, including that of the American Indian and Irish monks. Ailey integrated his dance company by using white dancers to play traditional black roles, thus breaking down the barriers of race in dance.