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.
History of Monterrey
After the country's independence from the Spanish Crown and the foundation of Mexico in 1821, the governments of Mexico and the United States fought the Mexican-American War, which resulted in the loss of more than half of Mexico's national territory. On 23 September 1846 General William J. Worth besieged the city and a battle between the two countries was fought from Cerro del Obispado to the Villa de Guadalupe, known as the Battle of Monterrey. American troops remained in the Mexican territory until 1848 and the Mexico-American War ended with the treaty of Guadalupe Hidalgo in which the conflicting parties agreed that the United States would acquire the territories of Alta California and New Mexico, and the territory between the Nueces River and the Rio Grande, claimed by the Republic of Texas.