Today is Cinco de Mayo. It is sometimes mistakenly thought of as a major Mexican holiday; it is, rather, a celebration of Mexican heritage and pride by people of Mexican descent living mostly in the United States – and, of course, non-Mexicans looking for an excuse to drink tequila.
In Mexico, Cinco de Mayo is celebrated primarily in the state of Puebla where it is called El Día de la Batalla de Puebla (The Day of the Battle of Puebla) observed to commemorate the Mexican army’s unlikely victory over French forces at the Battle of Puebla on May 5, 1862. France, under the leadership of Napoleon Number Three, sought to establish a Gallic empire in Mexico (possibly because things had gone so well for Napoleon Number One in Russia back in 1812). In 1861, a large French force landed at Veracruz sending the Mexican government into retreat. Moving toward Mexico City, the French army encountered heavy resistance near Puebla from a poorly equipped Mexican army of 4,500 men. The Mexicans were able to soundly defeat the 8,000-strong French army, considered the best in the world.
Wretched Richard's Almanac 