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.
Mexico–Republic of Texas relations
Republic of Texas–Mexico relations refers to the historical foreign relations between the Republic of Texas and Mexico. Relations were unofficially initiated in 1836 at the signing of the Treaties of Velasco, which de facto declared Texas independent from Mexico, though the Mexican Government never fully recognized Texas' Independence. The relations between the two countries, however hostile, continued until 1845 after the annexation of Texas by the United States, and the beginning of the Mexican–American War.