Mexico City as capital of the Viceroyalty of New Spain was the key point for ending the 11 year Mexican War of Independence.

Before the battle Agustín de Iturbide went to Córdoba to have a meeting with the Political Superior Chief,[Note 1] Juan O'Donojú, he left command of the troops around Mexico City to Luis Quintanar and Anastasio Bustamante.

On 19 August 1821, the insurgent, Nicolas Acosta, entered Azcapotzalco and took over the Rosario bridge with the purpose of attacking the royalist forces.

As soon as the battle began, the royalist general Manuel de la Concha went to his headquarters in Tacubaya for reinforcements.

The famous insurgent soldier Encarnación Ortiz also known as El Pachondo tried to rescue the artillery but was shot and killed.