Mexican War of Independence
Although Mexico gained its independence in September 1821, the marking of this historical event did not take hold immediately. The choice of date to celebrate was problematic, because Iturbide, who achieved independence from Spain, was rapidly created Emperor of Mexico. His short-lived reign from 1821–22 ended when he was forced by the military to abdicate. This was a rocky start for the new nation, which made celebrating independence on the anniversary of Iturbide's Army of the Three Guarantees marching into Mexico City in triumph a less than perfect day for those who had opposed him. Celebrations of independence during his reign were marked on September 27. Following his ouster, there were calls to commemorate Mexican independence along the lines that the United States celebrated in grand style its Independence Day on July 4. The creation of a committee of powerful men to mark independence celebrations, the "Junta Patriótica", organized celebrations of both September 16, to commemorate Hidalgo's grito and the start of the independence insurgency, and September 27, to celebrate actual political independence.
Military history of Mexico
The war for independence started on August 24, 1810, and was spearheaded by Miguel Hidalgo, a priest of Spanish descent and progressive ideas. After Napoleon I invaded Spain and put his brother on the Spanish throne, Mexican Conservatives and rich land-owners who supported Spain's Bourbon royal family objected to the comparatively more liberal Napoleonic policies. Thus an unlikely alliance was formed in Mexico: liberales, or Liberals, who favored a democratic Mexico, and conservadores, or Conservatives, who favored a Mexico ruled by a Bourbon monarch who would restore the old status quo. These two elements agreed only that Mexico must achieve independence and determine her own destiny.