The Mexican Frontier, 1821–1846 published by other historians. This work was supplemented by additional primary materials which he discovered in the archives that allowed him to delve further into certain areas. "The Mexican Frontier" examines the southwestern United States, specifically the areas now known as Arizona, California, New Mexico, and Texas, in the twenty-five years between Mexico's independence from Spain and the beginning of the Mexican–American War. This resulted in the transfer of control of the border areas to the United States. In the early days of the Republic of Mexico, these areas comprised its northern border, including the territories of Alta California and
Mexican War of Independence rule until the Hidalgo revolt of 1810. Elites in Mexico City in the seventeenth century did force the removal of a reformist viceroy, the Marqués de Gelves, following an urban riot in 1624 fomented by those elites. He attempted to eliminate corrupt practices by creole elites as well as rein in the opulent displays of the clergy's power, but ecclesiastical authorities in conjunction with creole elites mobilized urban plebeians to oust the viceroy. The crowd was reported to shout, "Long live the King! Love live Christ! Death to bad government! Death to the heretic Lutheran [Viceroy Gelves]! Arrest the viceroy!"