Evidence for the Traditional View of the Transmission of Gregorian Chant

The numerous musical variants in the manuscripts of classical Gregorian chant are mostly trivial, having little effect on the melodies. They are more readily understood as mishearings than as misreadings. The few substantive variants are always regional. Many variants involving the replacement of E or B by F or C, or using special neumes such as the salicus or trigon suggest that at one time microtones were used in the chant-a hypothesis supported by some theoretical evidence. The variants taken together show that the chant was fully fixed with respect to pitch before its dissemination throughout the Carolingian Empire and beyond, and hence that any period of improvisational or recreative performance must have occurred prior to that time.