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.
Gun laws in Mexico
Following Mexico's independence as the First Mexican Empire in 1822, the Political Provisional Regulation of the Mexican Empire in Article 54 made a reference to the carrying of prohibited arms (in Spanish: "...el porte de armas prohibidas...") and by 1824, following the establishment of the United Mexican States, it was declared that no person shall carry any type of weapon. The inclination to adopt a complete ban on firearms came as a precaution and attempt to prevent another armed insurrection that would put the new republic in jeopardy. After this measure, four years followed without war under President Guadalupe Victoria.