Courvoisier is a brand of cognac. Although there exists no evidence that Courvoisier cognac was the favorite drink of Napoleon Bonaparte, who died in 1821, before Courvoisier was officially established by Felix Courvoisier in 1835,the company website claims the following:
"The origin of our history goes back to the beginning of the 19th century with Emmanuel Courvoisier and his associate, Louis Gallois, running a wine and spirit merchant company, in the Parisian suburb of Bercy. In 1811 Napoleon visited their warehouses in Bercy and he was hosted by Louis Gallois, the Mayor, and Emmanuel Courvoisier. Legend has it that Napoleon I later took several barrels of cognac with him to St Helena, a treat much appreciated by the English officers on the ship who named it 'The Cognac of Napoleon'."