Mexican Cession Mexican Cession, with considerable local autonomy punctuated by several revolts and few troops sent from central Mexico, in the period from 1821–22 after independence from Spain up through 1846 when U.S. military forces seized control of California and New Mexico on the outbreak of the Mexican–American War. The northern boundary of the 42nd parallel north was set by the Adams–Onís Treaty signed by the United States and Spain in 1821 and ratified by Mexico in 1831. The eastern boundary of the Mexican Cession was the Texas claim at the Rio Grande and extending north from the headwaters of the Jojo
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