Spanish attempts to reconquer Mexico
Mexican independence was officially achieved on September 27, 1821, under the Treaty of Córdoba. Spain did not recognize the treaties, arguing that the viceroy Juan O'Donojú had no authority to recognize the independence of any overseas province. This situation was dangerous to the newly acquired independent status of the nation, which had not yet been recognized by any of the European powers that could support it, and the threat of Spanish reconquest was a constant worry to the leaders of the nascent regime. On May 13, 1822 decrees were issued by the government to imprison anyone who conspired against Mexico's independence.
Mexican War of Independence
In the early 19th century, Napoleon's occupation of Spain led to an outbreak of numerous revolts against colonial government across Spanish America. After the abortive Conspiracy of the Machetes in 1799, a massive revolt in the Bajío region was led by secular cleric Miguel Hidalgo y Costilla. His Grito de Dolores was the first stage of the insurgency for Mexican independence. Before 1810, there was no significant support for independence. Once the Hidalgo revolt was underway, it received major support only in the Bajío and parts of Jalisco.