The techniques of sparkling winemaking did not originate with the Benedictine monk Dom Pérignon, nor was the first purposely sparkling wine produced in the region of Champagne. Regardless, through centuries of refinement Champagne has become the world’s leading sparkling wine and the vinous embodiment of luxury and celebration.
I was just revisiting this study guide and found, "Blanc de Blancs: 100% Chardonnay is required" After re-reading the cahier des charges it does not seem to be the case. The only stipulation is that they must be made from 100% white grapes allowed in the AOP.
Wow, great catch! Thanks for bringing this to our attention.