The passage suggests that 'the African Union Church's hymn book' was

The passage does not provide evidence that the African Union Church's hymnbook influenced later works by Black authors. Instead, it emphasizes Porter's role in expanding the scope of what constitutes literature rather than detailing specific influences on subsequent literary works.

There is no information in the passage regarding the readership of the hymnbook during the 1920s compared to its initial publication. The focus is primarily on how Porter's bibliography challenged existing notions of literary classification rather than on the book's popularity over time.

The passage suggests that the hymnbook was not typically recognized as literature under the prevailing criteria of the 1920s. Therefore, it cannot be characterized as a well-known example of early African American literature prior to the reevaluation brought about by Porter's contributions.

The passage does not mention any confusion regarding the date of publication of the hymnbook. Instead, it highlights Porter's efforts to broaden the understanding of authorship and literature without implying that the hymnbook's publication date was misrecognized.