A wild “diabolus in musica” appeared on the Gloria part in Guillaume de Machaut’s (c. 1300–1377) Messe se Nostre Dame (composed before 1365).

This is just a minor indicator that the #tritone wasn’t as banned as the myth says. I’d bet that #Machaut didn’t get beheaded for writing this diatonic tritone in the #medieval times.

#DiabolusInMusica #GuillaumeDeMachaut