Short answers, pulled from the story.
Julia Ward Howe wrote the lyrics for Battle Hymn of the Republic on the night of the 18th of November 1861. She stayed at the Willard Hotel in Washington and composed the verses after hearing soldiers sing John Brown's Body during a public review of troops outside Washington D C.
Battle Hymn of the Republic first appeared on the front page of The Atlantic Monthly magazine in February 1862. Julia Ward Howe sold her adaptation for four dollars to The Atlantic Monthly before its publication that same month.
The melody began as a revivalist hymn called Say Brothers will you Meet Us in the late 1700s. Camp meeting singers passed this tune orally across the United States for decades before it appeared in print and became associated with the song.
Major artists have performed Battle Hymn of the Republic multiple times including Marian Anderson in 1953, Judy Garland in December 1963, Andy Williams in 1968, and Anita Bryant on January seventeenth 1971. These performances spanned television broadcasts, radio singles, and sporting events like Super Bowl V.
Dr Martin Luther King Jr used lyrics from Battle Hymn of the Republic in speeches delivered from steps of Alabama State Capitol building March twenty fifth 1965. He spoke again in Memphis Tennessee on evening April third 1968 delivering his final sermon I've Been to the Mountaintop before his assassination.