The army, composed of nearly 10,000 men, was named the Eastern Army, whose mission was to confront the French contingent of 6,000 soldiers commanded by the insolent General Charles Ferdinand Latrille.

Zaragoza knew beforehand that he had a difficult responsibility as well as a clear disadvantage in both arms and in discipline, for the Mexican army was in a precarious situation and was practically devoid of everything except for courage. Knowing of what stuff his men were made of, Zaragoza said to them: “Our enemies may be the world’s first citizens, but you are Mexico’s first sons and they want to wrest your homeland from you”.

Zaragoza headed east and decided to confront the invaders with an initial contingent of 4,000 troops in the area known as the Summit of Acultzingo. In this first meeting, Zaragoza did not intend to stop the passage of the French, but simply to let his soldiers gain experience, as many of them had no prior experience in battle. In this first skirmish, Napoleon’s powerful army lost nearly 500 men, while the Mexicans lost only 50 soldiers. In the face of this event, Zaragoza returned to his headquarters commenting to his soldiers, “The French fight well, but our soldiers are better at killing”.

Under orders from Juarez to stop the French at Puebla, Zaragoza prepared a quick plan for the plaza’s defense. Climbing to the top of Cerro de Guadalupe, he decided to mount two garrisons in the strongholds of the Loreto and Guadalupe forts with 1,200 men and to take on the French Army with another 3,500 men.

The battle began on May 5th when the interventionist army arrived at the city of Puebla. At 11:15 a.m., the first group formed by Mexican soldiers and indigenous Zacapoaxtla forces faced the French and managed to overcome the powerful attacks of the foreigners.

Zaragoza quickly positioned his soldiers in the dip between both hills and formed an angle between the forts and other key areas in the defense of the site.