Watch Free Online HD Moviesjoy. The recording of a concert by the Martinů Voices vocal choir, conducted by Lukáš Vasilek, at St. Wenceslas Church in Opava presents listeners with a repertoire of famous spirituals in spectacular and virtuoso jazz arrangements. Spirituals, a phenomenon of American culture, gained popularity primarily for their catchy melodies and rhythms, which formed the basis for the emergence of jazz in the early 20th century. The program features mainly arrangements by Henry Thacker Burleigh, an African-American composer whose spiritual music influenced the work of Antonín Dvořák, among others.