What exactly is Mexico celebrating on May 5th

On May 5, the anniversary of the Battle of Puebla is celebrated, in which the Army of the East defeated the French Army. The 6th Battalion of the National Guard of the State of Puebla, under the command of Colonel Juan Nepomuceno Méndez, was the first body of the Army of the East to face the French and repel the attack. Several French attacks were repelled by the resistance of the Mexican Army as is the case of the Zouaves (originally from Algeria), the elite regiment of the French infantry, who began a cautious ascent to the Fort of Guadalupe, but were received with bayonets and forced the French to retreat.

At half-past two in the afternoon, when the Mexicans began to glimpse the victory, Lorencez set out to launch the last assault, directing the Hunters of Vincennes and the Zuavos Regiment to Guadalupe. Zaragoza arranged for the Reforma Battalion of San Luis Potosí to come to the aid of the forts. After being repelled for the last time, the French Expeditionary Army forces began to flee completely dispersed. They retreated to the Hacienda Los Álamos, to finally retire to Amozoc. In the end, the Army of the East imposed itself on the French. General Ignacio Zaragoza sent a telegram to inform of the triumph of the Mexican forces.

"The arms of the Supreme Government have been covered in glory: the enemy has made supreme efforts to seize Cerro de Guadalupe, which attacked from the left and right for three hours: it was rejected three times in complete dispersion and is currently formed in battle, strong of more than 4,000 men, in front of the hill of Guadalupe, out of shot. I do not beat it, as I would like, because the Government knows (that) I do not have enough force for it. I calculate the loss of the enemy, who came to the pits of Guadalupe in his attack, in 600 or 700 between dead and wounded; 400 we will have had. Serve yourself give an account of this part to the President."- I. Zaragoza