As the Union Soldiers marched into battle, they sang "The John Brown Song," later known as "John Brown's Body," whose tune years later with the words changed became "Battle Hymn of the Republic."
Maya Hawke, daughter of Ethan Hawke, creator of the show, plays Annie Brown, one of the daughters of John Brown.
Principal photography began July 2019--the hottest July in recorded history.
The costumer for Hawke had difficulty when Hawke would sweat heavily, his arm tattoos would show through the wet white shirt. Eventually the costumer had to add a second layer to the sleeve to absorb the sweat to keep it from soaking through to the outer layer.
Originally envisioned as a big screen adaptation in 2014 with Liev Schreiber cast as John Brown & Jaden Smith cast as Henry "Onion" Shackleford. But the film never materialized.