The city of Madrid had been under the occupation of Napoleon's army since March 23, 1808. King Charles IV had been forced to abdicate in favour of his son Ferdinand VII, and at the time of the uprising both were in the French city of Bayonne at the insistence of Napoleon.

On the 2nd May a crowd began to gather in front of the Royal Palace in Madrid. Those gathered entered the palace grounds, and General Murat sent a battalion of grenadiers from the Imperial Guard to the palace along with artillery detachments. The latter opened fire on the assembled crowd, and the rebellion began to spread to other parts of the city.

What followed was street fighting in different areas of Madrid as the poorly armed population confronted the French troops. The repression following the crushing of the initial rebellion was harsh. Murat created a military commission on the evening of the 2nd May; this commission issued death sentences to all of those captured.

On the same 2nd May, in the nearby town of Móstoles, the arrival of the news of the repression prompted Juan Pérez Villamil, who was secretary of the Admiralty and prosecutor of the Supreme War Council, to encourage the mayors of the town, Andrés Torrejón and Simón Hernández, to sign a declaration of war calling all the Spaniards against the invaders.

Independence War had started.