Monterrey comprises, more or less, OTL Mexican states of Tamaulipas, Nuevo León, Cohahuila, Chiguagua, Durango, Sinaloa, Baja California Sur, northern Zacatecas, and northern San Luis Potosí. Also includes south and western Texas, and eastern New Mexico.
In 1816, several provinces in New Spain declared pro-Ferdinandist juntas, but the harsh represion of junta members by Ferdinand pushed many rebels north: to Louisiana, California and New Mexico.
Louisiana declared her independence in 1822, and the success of the independentist war aligned many peoples in the Monterrey and Santa Fe area to declare themselves independent.
In 1824, the authorities in Monterrey, Hermosillo and Santa Fe declared the independence of what they called New Mexico.
The independence war was prolonged given several attempts from Spain to conquer back New Mexico. During this process, California seceeded too (declararion of independence issued in 1833).
In 1846, after the battle of Río Bravo, in which 1130 Spanish regulars died, Spain recognized the independence of New Mexico, in the treaty of Havana.
Peace did not last long in New Mexico. Rivalries between Santa Fe and Monterrey, between centralists and federalists, between conservatives and liberals, broke in a complex civil war in 1849. By early 1851, a new liberal centralist constitution came as conclusion of the war.
In March 1852, a faction of mostly conservatives (both federalists and centralists) in Monterrey declared the Republic of Monterrey, opposed to the government in Santa Fe. By November 1852, the Monterrey fraction dominated most of the territory, including Santa Fe itself, burning and destroying all public buildings and sacking the city.
In February, 1853, most important cities were controled by this Monterrey fraction, but fighting continued in rural areas, with some warlordism.
In June, the governor of Arizona, with some popular support and the support of local warlords, declared the independence of Arizona, renewing hostilities with Monterrey. Originally supported by California, who saw a greater threat in Monterrey, Arizona managed to train a regular army and in a series of battles won over Monterrey, the Arizona governor defined current Arizona-Monterrey borders.
A truce was signed after the battle of Albuquerque, in August, 1854, but Monterrey did not recognize Arizona as independent until the new constitution of 1862.
The constitution of New Mexico of 1840 banned slavery, which was a small phenomenon in the territories. The subsequent constitutions of New Mexico, Monterrey and Arizona have kept the ban.
The Republic of Monterrey is a federal republic composed of states (estados, sing. estado). These states include:
- Baja California
- Nuevo León