A 17th-Century Monk’s 5040-Voice Canon
Guido of Arezzo, the monk who created the musical staff, also devised a 7-note chant that could be sung in 5040 different orders—exactly the number of ways to arrange seven distinct notes. His mathematical grid of intervals let singers rearrange pitches without breaking harmony, showing early composers used permutations as a creative tool.
💡 Fun detail:
If every unique ordering were sung once per second, it would take more than an hour and a half to perform the entire set.
Source: Oxford Music Online