From David Montejano, Anglos and Mexicans in the Making of Texas, 1836-1986, pp. 34-36.
Although the American presence generally represented a new class in an old Mexican society, it did not completely transform the traditional authority structure. On the contrary, the American merchants and lawyers merely affixed themselves atop the Mexican hierarchy. In some cases they intermarried and became an extension of the old elite. For individual families of the Mexican elite, intermarriage was a convenient way of containing the effects of Anglo military victory on their status, authority, and class position. For the ambitious Anglo  merchant and soldier with little capital, it was an easy way of acquiring land. The social basis for postwar governance, in other words, rested on the class character of the Mexican settlements.
These settlements were essentially a three-tiered society composed of landed elite, small land owners (rancheros) and peones. San Antonio in the 1830s, for example, was a highly structured class society. At the top were the prominent landed families, who lived in spacious flat-roofed stone houses; below them were the rancheros, who spent the greater part of their days working their cattle and horses and whose small adobe homes usually consisted of one sparsely furnished room; and at the bottom tier of the class order were the laborers, or jornaleros, who lived in jacales, which were nothing more than mud houses with thatched roofs. A prominent contemporary of the period, José María Rodríguez, described the “great distinction between the east and west side of the [San Antonio] river” in the following manner: “The west side of the river was supposed to be the residence of the first families here, and the descendants of the Indians and Spanish soldiers settled on the east side of the river. . . . Most of the Canary Islanders who lived on this [west] side took great pride in preventing any marriage with mixed races and when one did mix he lost his caste with the rest.” Although frontier conditions made this caste system somewhat fluid, and families could in generations pass from one caste to another, the lines themselves were quickly drawn. Moreover, they were distinctions that the American pioneers were quick to recognize and accept. Ample evidence points to an early accommodation between old and new elites. Although initially outside this Spanish-Mexican structure, the Anglo-Saxon pioneers were accepted–depending on their class, of course–as equals by the “Spanish” elite. By 1842, however, only six years after independence, the peaceful accommodation that had characterized Mexican-Anglo relations collapsed. The loss of land, the flight of the Mexican elite, and the Mexican War a few years later quickly eroded the influence of Mexicans.
In spite of this, San Antonio after the Civil War still had appearances, according to one resident, of a village “typical of Mexico then.” The “early Americans” had become acclimated, had intermarried in many instances, “and in turn kept up many of the customs of this quaint old Spanish town.” The town of about ten or twelve thousand inhabitants had a mingling of American, German, and French colonists with a large Mexican population. In the plaza could be heard “a babble of voices from three or four languages” but “almost everyone spoke Spanish and most of the business was conducted in this common language.” The resident observer concluded  that “the political border was at the Rio Grande, but Military Plaza was the commercial and social border between the countries.”
The Rio Grande settlements south and west of San Antonio differed little in their social structure. . . .