ABSTRACT
The Indians were aggressive; in fact, Ibarra was lucky to get out of Senora country with his expedition intact--and his problems with the natives discouraged Spanish settlement. In the mid-sixteenth century, as indicated by the various Spanish accounts and by an increasing amount of archaeology, there were a series of political units, each probably centered on a primate town, and each controlling a river valley or part of a valley. Archaeology has demonstrated that at least the Sonora valley was heavily settled in late pre-Spanish times. Jesuit Ignaz Pfefferkorn was in contact both with the Pima and with the Opata, and was well acquainted with the Serrana, the old Sonoran statelet region. Daniel T. Reff believes that the Spaniards in the period 1539-1565 may have actually been describing the Sonora valley when they talked of a rich area with many towns.
