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.
Mexico
Agustín de Iturbide became constitutional emperor of the First Mexican Empire in 1822. A revolt against him in 1823 established the United Mexican States. In 1824, a Republican Constitution was drafted and Guadalupe Victoria became the first president of the newly born country. Central America, including Chiapas, left the union. In 1829 president Guerrero abolished slavery. The first decades of the post-independence period were marked by economic instability, which led to the Pastry War in 1836. There was constant strife between Liberals, supporters of a federal form of government, and Conservatives, who proposed a hierarchical form of government.