From the data of the chroniclers and the archaeological testimonies, today we know that the indigenous agricultural techniques like the irrigation systems (called acequias by the Spaniards) and the cultivation in terraces or andenes (used in all the South American Andes to take advantage of the slopes of the mountains) show for the time of the contact the existence of an economic infrastructure that supposes the presence of a numerous native population in the Andean Mountain range, as well as the existence of a hierarchical political organization and a network of communications in all the zone.