The resulting prosperity of the mining regions of Bolivia stimulated the settlement of the north-western provinces of the Argentine. The miners needed provisions which could not well be raised in the neighbourhood of Potosi. There was a demand for cattle for beef, and for horses and mules for transportation. A solid economic foundation was thus provided for the plains settlements, and the enslavement of the Indians and the breeding of cattle went on apace. By the end of the sixteenth century north-western Argentine--the province of Tucuman, as it was then called--was the seat of many thriving settlements whose Spanish inhabitants were mostly pastoral. The Indians in the neighbourhood of each settlement had been reduced to slavery, and cultivated the fields that had been their fathers' for the benefit of their white masters. The Spanish proprietors lived like feudal lords, while the Spanish authorities left these remote regions largely to their own devices. Conditions in Cuyo, the western province just across the Andes from Santiago de Chile, were substantially the same. A political dependency of Chile, the few external relations it had were with that captaincy-general. The Spanish grantees ruled their Indian slaves in patriarchal fashion; agriculture was the principal occupation; pastoral industry was not so profitable as in Tucuman, and the region was more isolated. In both Tucuman and Cuyo Spanish rule was superimposed upon a previously existing commercial and social structure. There was no attempt to expel or destroy the aborigines. On the contrary, they were the sole labourers and their exertions the chief source of the wealth of their conquerors. There began a process of approximation and mutual assimilation between the Spaniards and their semi-civilised subjects. While the former continued to be a privileged and ruling caste, the latter absorbed much European knowledge from them. The Indian language long held its own alongside of the Spanish and is still spoken in many parts of the region. On the Atlantic side, among degraded peoples who had not progressed beyond the wandering and tribal stages of existence. Spanish settlement proceeded on entirely different lines. There existed no well-organised body politic, into whose control the conquerors could step with hardly an interruption to industry. Campaigns could not be made with the confident expectation of finding abundant accumulations of food _en route_. Expeditions among the squalid tribes were slow and dangerous and settlement stuck close to the rivers instead of following fearlessly across the plateau to the spots where the finest lands and the most flourishing Indian communities lay ready for the spoiler.