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.
Coahuila y Tejas
From the time Mexico became independent from Spain, there was public support for abolishing slavery. Fears of an economic crisis if all of the slaves were simultaneously freed led to a gradual emancipation policy. In 1823, Mexico forbade the sale or purchase of slaves, and required that the children of slaves be freed when they reached fourteen. Any slave introduced into Mexico by purchase or trade would also be freed. Many of the colonists in Texas, however, had already owned slaves and brought them to the new territory when they immigrated from the United States.