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.
Alta California
Mexico gained independence from Spain in 1821 upon conclusion of the decade-long Mexican War of Independence (not acknowledged by Spain until 1836). As the successor state to the Viceroyalty of New Spain, Mexico automatically included the provinces of Alta California and Baja California as territories. Alta California declared allegiance to the new Mexican nation and elected a representative to be sent to Mexico. On November 9, 1822, the first legislature of California was created. With the establishment of a republican government in 1824, Alta California, like many northern territories, was not recognized as one of the constituent States of Mexico because of its small population. The 1824 Constitution of Mexico refers to Alta California as a "territory".