Mexican Americans included New Mexican Hispanos and Pueblo Indians and Genizaros, Tejanos, Californios and Mission Indians have existed since the area was part of New Spain. The majority of these historically primarily Hispanophone populations eventually adopted English as their first language as part of their overall Americanization. Approximately ten percent of the current Mexican-American population are descended from the early colonial settlers who became U.S. citizens in 1848 via the Treaty of Guadelupe Hidalgo which ended the Mexican–American War. Although most of the original Mexican American population were officially deemed white citizens by the treaty, they have faced and continue to face
Spanish conquest of the Aztec Empire "The Aztecs Under Spanish Rule: A History of the Indians of the Valley of Mexico, 1519–1810" (1964) were central in reshaping the historiography of the indigenous and their communities from the Spanish Conquest to the 1810 Mexican independence era. Scholars who were part of a branch of Mesoamerican ethnohistory, more recently called the New Philology have, using indigenous texts in the indigenous languages, been able to examine in considerable detail how the indigenous lived during the era of Spanish colonial rule. A major work that utilizes colonial-era indigenous texts as its main source is James Lockhart's "The Nahuas After the