Harry T. Burleigh (1866 – 1949), a great singer and expert on spirituals is associated with this song but it was written before he was born. The author is unknown. The Golden Gate Quartet, Paul Robeson, and Louis Armstrong all recorded wonderful versions of it. The story is about the exodus of the Hebrews (people of Israel) from Egypt after 300 years of slavery.
Harry T. Burleigh – Wikipedia