It is celebrated nationwide in the United States and regionally in Mexico, primarily in the state of Puebla, where the holiday is called El Día de la Batalla de Puebla (English: The Day of the Battle of Puebla).
The date is observed in the United States as a celebration of Mexican heritage and pride, and to commemorate the cause of freedom and democracy during the first years of the American Civil War.I
In the state of Puebla, the date is observed to commemorate the Mexican army‘s unlikely victory over French forces at the Battle of Puebla on May 5, 1862, under the leadership of General Ignacio Zaragoza Seguín.
Contrary to widespread popular belief, Cinco de Mayo is not Mexico’s Independence Day-the most important national patriotic holiday in Mexico-which is actually celebrated on September 16.
Cinco de Mayo has its roots in the French occupation of Mexico, which took place in the aftermath of the Mexican-American War of 1846-48, the Mexican Civil War of 1858, and the 1860 Reform Wars. These wars left the Mexican Treasury in ruins and nearly bankrupt. On July 17, 1861, Mexican President Benito Juárez issued a moratorium in which all foreign debt payments would be suspended for two years.
In response, France, Britain, and Spain sent naval forces to Veracruz to demand reimbursement. Britain and Spain negotiated with Mexico and withdrew, but France, at the time ruled by Napoleon III, decided to use the opportunity to establish a Latin empire in Mexico that would favor French interests, the Second Mexican Empire.
The French invasion
Late in 1861, a well-armed French fleet stormed Veracruz, landing a large French force and driving President Juárez and his government into retreat.[Moving on from Veracruz towards Mexico City, the French army encountered heavy resistance from the Mexicans near Puebla, at the Mexican forts of Loreto and Guadalupe.
The 8,000-strong French army attacked the much more poorly equipped Mexican army of 4,000. Yet, on May 5, 1862, the Mexicans managed to decisively crush the French army, one which, according to an article in Philadelphia’s The Bulletin daily newspaper, was the best army of the time.
The Mexican victory
The victory represented a significant morale boost to the Mexican army and the Mexican people at large. In the description of The History Channel, “Although not a major strategic win in the overall war against the French, Zaragoza’s success at Puebla represented a great symbolic victory for the Mexican government and bolstered the resistance movement. “The description of Time magazine was: “The Puebla victory came to symbolize unity and pride for what seemed like a Mexican David defeating a French Goliath. “It helped establish a much-needed sense of national unity and patriotism.