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.
Battle of Puebla
A common misconception in the United States is that Cinco de Mayo is Mexico's Independence Day, the most important national patriotic holiday in Mexico. Mexico celebrates Independence Day on the 16th of September, commemorating the beginning of the war of Independence (September 16, 1810, the "Cry of Dolores"). Mexico also observes the culmination of the war of Independence, which lasted 11 years, on the 27th of September.