432 Hz and the Solfeggio Frequencies
The six frequencies were derived by numerology from a Bible verse in a single 1999 book, with no source predating it. The claim that 432 Hz is more ancient or natural only became possible after the modern tuning standard of 440 Hz was formally fixed in 1955 — the 'ancient' alternative is defined entirely in reference to a mid-twentieth-century standard.
Joseph Puleo & Leonard Horowitz, Healing Codes for the Biological Apocalypse (1999); ISO 16 (1955), fixing A=440
A set of six musical tones marketed as an ancient sacred tuning, and the claim that 432 Hz is the true natural pitch of music.