Cinco de Mayo officially commemorates the anniversary of an early victory by Mexican forces over French forces in the Battle of Puebla on May 5, 1862. It is not the anniversary of the defeat and expulsion of the French forces by the Mexicans, which occurred in 1867.
People celebrate Cinco de Mayo because it's the anniversary of an early victory by Mexican forces over French forces in the Battle of Puebla on May 5, 1862. Hope this helps
