From The Comanche Empire, by Pekka Hämäläinen (Yale U. Press, 2008), pp. 26-27:
Utes also introduced Comanches to European crafts. Having traded regularly in New Mexico since the 1680s, Utes had accumulated enough guns and metal tools to pass some of them on to their Comanche allies, who now moved, literally overnight, from the Stone Age to the Iron Age. Although Comanches used the new technology to replace their traditional tools and elaborate on their old techniques, not to realign their basic economic system, it was a momentous leap nonetheless. Iron knives, awls, needles, and pots were more durable and effective than their stone, bone, and wooden counterparts, making the daily chores of hunting, cutting, scraping, cooking, and sewing faster and easier. Spanish laws prohibited the sale of firearms to Indians, but the ban was widely ignored in New Mexico’s trade fairs, especially in the northern parts of the province. The few guns available at the fairs were cumbersome and fragile flintlocks, but they nevertheless profoundly changed the nature of intertribal warfare. Firearms allowed Comanches to kill, maim, and shock from the safety of distance and to inflict wounds that the traditional healing arts of their enemies were unaccustomed to treating. And, like horses, firearms gave Comanches access to an unforeseen source of energy—gunpowder—further expanding the world of new possibilities.
With Ute assistance, Comanches incorporated themselves into the emerging slave raiding and trading networks on New Mexico’s borderlands. By the time Comanches arrived in the region, commerce in Indian captives was an established practice in New Mexico, stimulated by deep ambiguities in Spain’s legal and colonial system. Although thousands of Pueblo Indians lived within the bounds of Spanish-controlled New Mexico, strict restrictions prohibited their exploitation as laborers. Encomienda grants of tributary labor, the economic keystone of early Spanish colonialism in the Americas, were abolished in New Mexico in the aftermath of the Pueblo Revolt. The repartimiento system of labor distribution continued, allowing the colonists to pool and allot Pueblo labor for public projects, but that system operated on a rotating basis, making Indian laborers a communal rather than a personal resource. Most Pueblo Indians, furthermore, were at least superficial Christian converts, whose exploitation was strictly regulated under Spanish law. Eager to obtain personal slaves to run their kitchens, ranches, fields, and textile workshops—and to reinforce their fragile sense of honor and prestige—Spanish elite turned to captive trade in indios bárbaros, savage Indians. Spanish laws specifically prohibited the buying, selling, and owning of Indian slaves, but the colonists of New Mexico cloaked the illegal traffic as rescate (ransom or barter), whereby they purchased captured Indians from surrounding nomadic tribes, ostensibly to rescue them from mistreatment and heathenism. In theory, these ransomed Indians were to be placed in Spanish households for religious education, but in practice many of them became common slaves who could be sold, bought, and exploited with impunity.
Utes had first entered New Mexico’s slave markets as commodities seized and sold by Spanish, Navajo, and Apache slave raiders, but the allied Utes and Comanches soon inserted themselves at the supply end of the slave traffic. When not raiding New Mexico for horses, Utes and Comanches arrived peacefully to sell human loot. Their raiding parties ranged westward into Navajo country and northward into Pawnee country to capture women and children, but their main target were the Carlana and Jicarilla Apache villages in the upper Arkansas basin at the western edge of the southern plains. Traffic in Apache captives mushroomed in New Mexico. By the late seventeenth century, the people in New Mexico possessed some five hundred non-Pueblo Indian captives and were emerging as major producers of slave labor for the mining camps of Nuevo Vizcaya and Zacatecas; they even sent slaves to the tobacco farms in Cuba. By 1714 slave trade had become so widespread in New Mexico that Governor Juan Ignacio Flores Mogollón saw it necessary to order all Apache captives baptized before taken “to distant places to sell.” Many of these Apaches were purchased from Utes and Comanches, whose mutually sustaining alliance had put them in a position of power over their neighboring Native societies.
By the early eighteenth century, the Ute-Comanche coalition dominated the northern borderlands of New Mexico. The allies shut off Navajos from the prime trading and raiding locales in New Mexico and treated the colony itself as an exploitable resource depot.