Early African-American spiritual autobiographies were published in the late 18th and early 19th centuries. Authors of such narratives include James Gronniosaw, John Marrant, and George White. William L. Andrews argues that these early narratives "gave the twin themes of the Afro-American 'pregeneric myth'—knowledge and freedom—their earliest narrative form". These spiritual narratives were important predecessors of the slave narratives which proliferated the literary scene of the 19th century. These spiritual narratives have often been left out of the study of African-American literature because some scholars have deemed them historical or sociological documents, despite their importance to understanding African-American literature as a whole.