The Battle of Cinco de Mayo, 1862, also known as "La Batalla de Puebla" (the Battle of Puebla),
actually took place almost 41 years after Mexico won its Independence.
Even after winning its Independence, Mexico suffered numerous setbacks in its attempt to form a stable republic. This included the Mexican-American War (1846-1848) won by the United States, which resulted in Mexico surrendering approximately half of its territory.
Following this war, Mexico suffered a severe economic crisis in the 1850's. In 1861, French, Spanish and English troops went to Mexico to collect debts that the newly elected Democratic President, Benito Juarez, was unable to pay. The English and Spanish came to agreements with the new President and left. The French, however, had visions of a Mexican Empire under the rule of the French Prince Maximilian and his ambitious wife, Carlotta.
Although the French Army had not been defeated in 50 years, it was defeated by a small band of Mexicans under the command of General Zaragosa in the City of Puebla as it marched towards Mexico City.
The Mexicans were equipped with only the most rudimentary arms, like machetes, picks, forks and other implements usually associated with farming, a striking contrast to the fine equipment in the hands of the French. Due to their small numbers and inferior armament, the Mexicans resorted to unorthodox methods, taking advantage of the weather conditions, stampeding cattle, and using the distraction of the cavalry.
As time passed, the French brought in more troops and attacked again, this time successfully, opening the way to conquest of Mexico City and the installation of Emperor Maximilian, who ruled for 4 years until his execution in 1876.