The authenticity of a monument or site is increased when the original function is continued and corresponds to the present use. It is also authentic, though to a lesser degree, when a change in use is dignified and compatible with the original and total reading of the building. Any intervention that will change the original or the historic functions of a monument or site must conform to the spirit of the building and must allow for a return to the original use. This implies the conservation of the original spaces, design and materials. All considerations of authenticity must include the natural and built environments, as well as the cumulative historic context in which the monument or site is located.
Cultural elements are also inseparable from the material context.
Interventions cannot refer exclusively to a monument or group of monuments, but must include integrally the setting, including all the values of its authenticity. In addition, it is necessary to go beyond the cumulative historic context to include visual aspects, avoiding alterations and additions that will affect the overall integrity.