Heck, you can argue that the perfect fifth was banned at one point, or the use of Cantus Firmus. I manage to ruffle feathers when I play traditional English tunes on my electric guitar. I can think of no better harmony text than Gradus an Parnassus (Joseph Fux), and M.Ted, if you see this, I bet that you have a copy on your shelf. Of course, he doesn't mention Musica Ficta.

Lucius

PS: M.Ted, you postings are delightful and well considered. Thanks for reminding us about the dominant seventh.