The French were advancing toward Mexico City, and were blocked by Mexican troops at Puebla.

During the winter, the French prepared for a new campaign in spring 1863, while in Puebla, Mexican forces under the command of General Ortega built new fortifications, including Fuerte ("fort") San Javier.

The siege began on 16 March with an encircling movement led by Generals Bazaine and Douay.

On 29 March, French troops made the first assault on Fort San Javier.

On 25 April, after failing to capture the convent of Santa Ines, the French decided to hold their position and wait for siege artillery to arrive.