History of Hispanic and Latino Americans in the United States
In 1821, Mexico gained independence from Spain, annexing the southwest of the present United States, including Arizona. As missions began to wither, Mexico began auctioning off more land, causing the Pimería Alta and the Apachería to shrink as territory expanded. In the meantime, American mountain men began to enter the region, looking to trap beavers for their pelts. In 1836, Texas declared independence from Mexico and claimed much of the territory in the northern lands of Mexico. When the United States annexed Texas in 1846 over the strong objections of the Mexican government, U.S. troops moved into disputed territory. The hostilities erupted in the Mexican–American War (1846–1848). The U.S. occupied Mexico City and forced the newly founded Mexican Republic to give up its northern half, including the later Arizona.
Miguel Ramos Arizpe
The insurgency for Mexican independence that began with Father Miguel Hidalgo's 1810 uprising and carried on by Father José María Morelos, and Vicente Guerrero during the 1810s was at a military stalemate with royalist forces. With the 1820 Spanish Constitution, the power of the Roman Catholic Church in Mexico was threatened. Royalist military officer Agustín de Iturbide made an alliance with Guerrero, and under the Plan de Iguala declaring Mexico's independence, which was achieved in 1821. The formation of the new Mexican state initially involved a constituent congress, but Iturbide seized power and declared himself Agustín I, emperor of Mexico. Ramos Arizpe returned to Mexico in 1822, when opposition to Iturbide was coalescing. He was "instrumental in mobilizing the provinces and drafting the Plan of Casa Mata," which called for the overthrow of Iturbide.