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.
Mexico–United States border
In the mid-16th century, after the discovery of silver, settlers from various countries and backgrounds began to arrive in the area. This period of sparse settlement included colonizers from different backgrounds. The area was part of New Spain, but due to the lack of population and the diverse citizenry it had, it did not seem to belong to any country. This period lasted until the early 19th century, at which point the United States bought the lands known as the Louisiana Purchase from France and began to expand steadily (militarily) westward in its pursuit of Manifest Destiny.
The border itself was not clearly defined and remained so until the Mexican colony became independent from Spain and entered a period of political instability. Mexico attempted to create a buffer zone at the border that would prevent possible invasion from the North. The Mexican government encouraged thousands of their own citizens to settle in the region that is now known as Texas and even offered inexpensive land to settlers from the United States in exchange for populating the area. The influx of people did not provide the defense that Mexico had hoped for and instead Texas declared its independence in 1836, which lasted until 1845 when the U.S. annexed it.