The French troops encounter strong resistance in Puebla led by one of Juárez's trusted men, General Ignacio Zaragoza, who defeats the foreigners on May 5, 1862 (May 5 is celebrated today as one of Mexico's two national holidays).

The following May, Puebla is surrounded once again by French troops, who lay siege to the city for two months until it surrenders.

The fall of Puebla means easy access to Mexico City, and Juárez decides to evacuate the capital after receiving approval from congress.