Cinco de Mayo (Spanish for "fifth of May") is a celebration of Mexican heritage and pride, commemorating the Mexican army's unlikely victory over French forces at the Battle of Puebla on May 5, 1862. Cinco de Mayo is not Mexico's Independence Day (September 16, 1810), which is considered the most important national patriotic holiday in Mexico. Perhaps because of its lesser historic significance for Mexico, Cinco de Mayo is not observed throughout most of Mexico (with the exception of Puebla) and is instead celebrated primarily in the United States.
The Battle of Puebla was important for at least two reasons. First, although considerably outnumbered, the Mexicans defeated a much better-equipped French army, which at the time was the most powerful military force in the world. Second, some scholars including José Antonio Burciaga believe that had the French defeated Mexico at Puebla, France would have aided the South in the American Civil War in order to free Southern ports of the Union Blockade. During this time Confederate General Robert E. Lee was enjoying success, and French intervention could have had an impact on the Civil War.