Cinco de Mayo - The national arms have been covered with glory

5 de Mayo, not our Independence Day.

On this was day we commemorate the Mexican Army's unlikely victory over the French Empire at the Battle of Puebla, on May 5, 1862, under the leadership of General Ignacio Zaragoza. (wikipedia)

The General Ignacio Zaragoza sent a letter to President Juárez which contains the famous quote "The national arms have been covered with glory".

As a consequence the United States avoided an invasion from the possible alliance between Confederates and British/French, becuase USA was divided fighting (the American Civil War), and when the town where General Ignacio Zaragoza was born  (in Texas) knew about the victory, they started to celebrate, becoming a mexican-american celebration.

The events that lead to the Battle of Puebla , go back to Mexican civil war (know as The Reform War) when President Juárez suspended payments to France, Spain and Britain which met in London to form the Tripartite Alliance and landed in Veracruz, the major port of Mexico.

The British and Spanish withdrew, leaving the French to march alone on Mexico City. On his way, the french found the Mexican Army near to Puebla and you already know the rest.