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 dominant figure of the second quarter of 19th century Mexico was the dictator Antonio López de Santa Anna. During this period, many of the territories in the north were lost to the United States. Santa Anna was the nation's leader during the conflict with Texas, which declared itself independent in 1836, and during the Mexican–American War (1846–48). One of the memorable battles of the U.S. invasion of 1847 was when a group of young Military College cadets (now considered national heroes) fought to the death against a large army of experienced soldiers in the Battle of Chapultepec (September 13, 1847). Ever since this war many Mexicans have resented the loss of much territory, some by means of coercion, and more territory sold cheaply by the dictator Santa Anna (allegedly) for personal profit.