With the Louisiana Purchase in 1803, the Americans acquired territory that included a portion of Comancheria, but during the next twenty years, American penetration of the Great Plains focused on the fur trade of the Missouri River. On the southern Plains, French traders, now American citizens, continued their contacts with Wichita and Comanches. They were soon joined by an increasing number of Americans. Since much of the trade was conducted through the Wichita, Comanches remained distant and mysterious. American Indian agents in Louisiana were urged to make contacts with the "Hietans."