This is a history of the Comancheros, or Mexicans who traded with the Comanche Indians in the early Southwest. When Don Juan Bautista de Anza and Ecueracapa, a Comanche leader, concluded a peace treaty in 1786, mutual trade benefits resulted, and the treaty was never afterward broken by either side. New Mexican Comancheros were free to roam the plains to trade goods, and when Americans introduced, the Comanches and New Mexicans even joined in a loose, informal alliance that made the American occupation of the plains very costly. Similarly, in the 1860s the Comancheros would trade guns and ammunition to the Comanches and Kiowas, allowing them to wreck a gruesome toll on the advancing Texans.