Conversation so far:
who wrote the lyrics to the black national anthem
Author and activist James Weldon Johnson wrote the words of the Negro National Anthem as a poem, which his brother John then set to music.
when did james weldon johnson write the words to the black national anthem
Lift Every Voice and Sing was written by James Weldon Johnson at a pivotal time, when Jim Crow was replacing slavery and African-Americans were searching for an identity.

Question: how did the song become the national anthem
Self-contained rewrite: how did the song Lift Every Voice and Sing become the black national anthem