Cinco de Mayo (Spanish for "fifth of May") is a holiday held on May 5 that commemorates the Mexican army's unlikely victory over Frenchforces at the Battle of Puebla on May 5, 1862, under the leadership of General Ignacio Zaragoza Seguín.[2][3] It is celebrated primarily in the state of Puebla and in the United States.[4][5][6][7] While Cinco de Mayo sees limited significance in Mexico itself, the date is observed nationwide mostly in the United States as a celebration of Mexican heritage and pride.[8] "Cinco de Mayo is not a Mexican holiday—it is anAmerican Civil War holiday, created spontaneously by Mexicans and Latinos living in California who supported the fragile cause of defending freedom and democracy during the first years of that bloody war between the states."[9]Read more here:
http://en.wikipedia.org/wiki/Cinco_de_Mayo