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.
https://www.champagne.fr/en/terroir-appellation/appellation/recognition-of-the-champagne-appellation
Official champagne website credits delimitation to July 22,1927, not 1908. Any other article pointing to what exactly happened in 1908?
It appears, I cannot completely confirm this, that the French government made an announcement it planned to delimited the region of Champagne in 1908. This was due to many issues including but not limited to poor vintages from 1902-1908, phylloxera and collusion of the large Champagne houses to use grapes from outside the region of Champagne itself including the Loire and Languedoc. The Champagne Riots then broke out soon afterwards and World War I quickly followed on the heels of the riots.