in the 1600s–early 1800s Scottish clans would burn a cross to signifiy they needed a rally of local troops and they were at war or under attack
in 1905 white supremacist Thomas Dixon Jr wrote a romance novel about the KKK (lmao), it featured this motif in the latter half where the fictional klansmen rally the fictional local residents heroically to side, ending with everyone burning crosses to show how the South had been “saved”
this motif grew in popularity in other white supremacist novels and in DW Griffith’s racist paean “Birth of a Nation” (1915)
this inspired the KKK to really burn crosses 10 months later after the film on Stone Mountain GA (biggest confederate memorial)
Then KKK vigilantes adopted the motif and popularized it throughout the 1930s and 1950s.
That’s very helpful thanks!
Thanks for providing this background material. TIL!