Alianza Hispano-Americana 

During the mid to late 19th century, Mexicans and Anglos were living side-by-side in many cities and towns throughout the Southwest. In Tucson, the first Anglos settled during the 1850s. They enjoyed a close association with their Hispanic neighbors, both socially and in business, and intermarriage was more common than not. During the 1870s, as the Anglo population rapidly increased, racial tension — especially among the labor classes — developed.