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.
Liberal Party (Mexico)
When Mexico achieved its independence in 1821, the Mexican political life was altered by constant struggles between Liberals and Conservatives. The Liberal Party enacted the Federal Constitution of 1857, which along with the Plan of Ayutla (1854) and other liberal reforms polarized Mexican society to lead the Reform War (1857–1861), the Second French Intervention in México (1862–1867) and the Second Mexican Empire (1863–1867).