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.
First Mexican Republic
The First Mexican Republic, known also as the First Federal Republic (), was a federated republic and nation-state officially designated the United Mexican States (, ). "Independence transformed Mexico from Spain's largest and most prosperous colony to a sovereign nation suffering economic decline and political strife." The First Mexican Republic lasted from 1824 to 1835, when conservatives under Antonio López de Santa Anna transformed it into a centralized state, the Centralist Republic of Mexico.