After the second millennium BC, the northwest of the Iberian Peninsula was settled by human societies organized into tribes that inhabited high sites called "Castros". Given the similarity between the buildings of these settlers in different locations, it can be said that the "Castro culture" developed in this area from the Portuguese Minho. to Galicia and Spanish Asturias, reaching its climax in the second century BC. The archaeological site of Sitania de Preteros is one of the most important examples of this culture, and the fact that it is located on hilltops reflects the ability of the inhabitants to better defend themselves from intruders and to observe the movements of strangers.