History
There are a lot of theories about the history of beheading champagne. All of them begin during
the first half of the 19th century.

One theory states that Napoleon after each victory gave his officers bottles of champagne, which they, as a gesture of celebration, beheaded with their swords.

Another theory tells about Madame Clicquot, who entertained Napoleons soldiers in exchange for protection of her land. When the soldiers rode off Madame Clicquot gave them bottles of champagne, which they opened with their swords. This theory is not very likely to be true since the soldiers wouldn’t be able to drink out of the beheaded bottles without cutting
themselves.

The most likely theory says that Russian Cossacks started the tradition. After Napoleon defeat in 1814 a lot of Russians lived in Champagne and Paris. Also an entire Russian army was stationed at Reims. Beheading champagne might be an extension of the tradition where one is supposed to break the glass after toasting to the tsar.