September 16, the anniversary of the day the Grito de Dolores was issued and the war for independence from Spain was inaugurated. Mexican Independence Day is celebrated on September 16th, the day the Grito de Dolores was issued and the war for independence from Spain was inaugurated. Most of the independence leaders were captured and executed by the Spanish Crown forces, and in a twist of fate, a criollo royalist switched sides in 1820 and had himself crowned emperor of an independent Mexico. Ultimately, a republic was established, but wars between the conservatives and liberals continued unabated. Mexico was also repeatedly attacked by the French and lost much of its national territory to the United States. For this reason, the victory over the French on the fifth of May 1862, was elevated as a holiday, and a symbol of Mexican determination to defend the patria. As a result, North Americans frequently assume that May 5 is Independence Day.