Mesoamerican chronology
Mexico became independent from Spain in 1821, with some participation of indigenous in decade-long political struggles, but for their own motivations. With the fall of colonial government, the Mexican state abolished distinctions between ethnic groups, that is the separate governance for indigenous populations in the "República de Indios". The new sovereign country made, in theory at least, all Mexicans citizens of the independent nation-state rather than vassals of the Spanish crown, with different legal standing. A long period of political chaos in the post-independence period among white elites largely did not affect indigenous peoples and their communities. Mexican conservatives were largely in charge of the national government and kept in place practices from the old colonial order. However, in the 1850s, Mexican liberals gained power and attempted to formulate and implement reforms that did affect indigenous communities, as well as the Catholic Church. The Mexican Constitution of 1857 abolished the ability of corporations to hold land, which aimed at taking assets out of the hands of the Catholic Church in Mexico and forcing indigenous communities to divide their community-held lands. Liberals' aimed at turning indigenous community members pursuing subsistence farming into yeoman farmers holding their own land. Mexican conservatives repudiated the liberal reform laws since they attacked the Catholic Church, but indigenous communities also participated in a three-year civil war. In the late nineteenth century, liberal army general Porfirio Díaz, a Mestizo did much for modernizing Mexico and integrating it into the world economy, but there were renewed pressures on indigenous communities and their lands. These exploded in certain areas of Mexico during the ten-year long civil war, the Mexican Revolution (1910-1920). In the aftermath of the Revolution, the Mexican government attempted simultaneously shore up indigenous culture, while at the same time also attempting to integrate the indigenous as citizens of the nation, turning indigenous into peasants ("campesinos"). This has proved more difficult than policy planners imagined, with resilient indigenous communities continuing to struggle for rights within the nation.
Presidio San Agustín del Tucsón
When Mexico achieved its independence from Spain in 1821, the Tucson Presidio still had a Spanish garrison that accepted Mexican freedom, likely because the Spanish aristocracy's hold on northern Sonora wasn't broken as result of the war. The aristocracy supported the independence of their country which fueled the rebellion, many also led the armies that won the war. Since 1775 and even longer due to the Pima villages, Tucson has always been inhabited, unlike several other Spanish settlements in the area. During the Mexican period at least seventy-five percent of Tucson was populated by Native Americans. After independence Mexico slipped into a depression and frontier colonization quickly became under-supplied with both men and food, old alliances between Spain and the natives ended. Other tribes continued to be peaceful, the Pimas remained friendly along with Yaquis and a few other groups in southern Arizona. Apaches remained a serious threat and most of the Spanish frontier settlements in Arizona and New Mexico were abandoned and the populations fled south. Generally the Mexicans remained only in the coastal states of Texas and California, creating more Indian country in between Mexico City and California. Landlocked settlements in what is now northern New Mexico survived with Tucson and a few other mission towns such as the San Xavier and the Tumacacori Mission. Apaches continued raiding and skirmished with Mexicans just outside the Presidio several times, they raided the livestock just like they did the Spanish herds. The Mexicans were less able to defend themselves due to the depression.