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
Historiography of Colonial Spanish America disdain. An important example is Mexico's conservative politician and intellectual Lucas Alamán. His five-volume "Historia de Mejico" is the country's first history, covering the colonial era up to and including the struggle for independence. Alamán viewed crown rule during the colonial era as ideal, and political independence that after the brief monarchy of Agustín de Iturbide, the Mexican republic was characterized by liberal demagoguery and factionalism. Writing in the mid-nineteenth century, Mexican liberal Vicente Riva Palacio, grandson of insurgent hero Vicente Guerrero, wrote a five-volume history of the colonial era from a liberal viewpoint, During the era of Porfirio Díaz