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
From 1815 to 1821 most of the fighting for independence from Spain was done by small and isolated guerrilla bands. From these, two leaders arose: Guadalupe Victoria (born José Miguel Fernández y Félix) in Puebla and Vicente Guerrero in Oaxaca, both of whom gained allegiance and respect from their followers. Believing the situation under control, the Spanish viceroy issued a general pardon to every rebel who would lay down his arms. After ten years of civil war and the death of two of its founders, by early 1820 the independence movement was stalemated and close to collapse. The rebels faced stiff Spanish military resistance and the apathy of many of the most influential criollos.