My research concerns the changes that occurred in the Andes during the Inka and Spanish conquests. To understand these changes, I compared two different areas: the Huari province in the Peruvian North-Central Andes, and the Calchaqui Valley in the North-western Argentina. In the last fifteen years I have worked and researched in both areas, and on the basis of this experience, I believe this approach offer opportunities for interesting cross-comparisons. The interpreting keys that I have chosen, to explore the processes of change in these two areas during the conquests, are the ancestor cult and the sacred landscape, both crucial elements in the Andean belief system.