Cinco de Mayo (Spanish for "fifth of May") is a celebration, primarily in Puebla,
Mexico, to commemorate the Mexican army’s victory over French forces at the
Battle of Puebla on May 5, 1862 and is observed in the United States as a way
to recognize Mexican heritage and pride. It is not to be confused with Mexico’s
Independence Day, the national patriotic holiday in Mexico which is celebrated
on September 16.  
 

A depiction of the Battle of Puebla on May 5, 1862, under the
leadership of General Ignacio Zaragoza Seguín (below).

General Ignacio Zaragoza