Today is Cinco de Mayo and while you might know the day, do you know what it means?

It means “Fifth of May” in Spanish and while some might think it commemorates Mexico’s Independence Day, it actually doesn’t. Also known as the anniversary of the Battle of Puebla, it marks a victory by a ragtag group of mestizo and Zapotec forces over the French troops of Napoleon III.

In 1861, Mexico declared a temporary moratorium on repaying foreign debts. The country was in a desperate financial crisis after years of internal strife. In retaliation, British, Spanish and French troops invaded.

By April 1862, Britain and Spain had negotiated with Mexico and withdrew their troops. France decided to use the situation to create an empire and sent a fleet to storm Veracruz. President Benito Juarez and the government were forced into hiding.

General Charles Latrille de Lorencez sent 6,000 troops to attack Puebla de Los Angeles, a small town in east-central Mexico, certain that they would be victorious. Juarez rounded up 2,000 men, many of them either Indigenous Mexicans or of mixed ancestry, to fight back, led by Texas-born General Ignacio Zaragoza.

The assault began on May 5, 1862 and lasted from daybreak until early evening, when the French troops retreated. Estimates of French losses range from 500-1,000 men, while fewer than 100 Mexicans were killed in the battle.

While not a major strategic win, the battle was a huge symbolic victory and boosted the resistance movement. After military and political support from the U.S., who could finally render aid after the Civil War, France withdrew in 1867. Austrian Archduke Ferdinand Maximilian, who had been declared Emperor of Mexico in 1864 by Napoleon III, was captured and executed by Juárez’s troops that same year. 

Today, Cinco de Mayo is primarily celebrated in the State of Puebla, but other parts of the country also take part in celebrations. In the U.S., it’s considered a celebration of Mexican heritage and culture, with parades, folk dancing, mariachi music and traditional foods.

Activists began raising awareness of the holiday in the U.S. back in the 1960s, partly because they identified with the victory of indigenous Mexicans over European invaders.

Mexican Independence Day is observed on Sept. 16, the anniversary of the revolutionary priest Miguel Hidalgo y Costilla’s famous 1810 “Grito de Dolores” or “Cry of Dolores,” referring to the city of Dolores Hidalgo, Mexico. It was a call to arms that was essentially a declaration of war against the Spanish colonial government.