During the development of works of historical content it is expected to examine the issue of the sources. From the beginning of the science of history sources were used, “questioned” and became the object of debate. Not only whether they are sincere or misleading, valid, ignorant, authentic or falsified. But also regarding the role they can continue to play in the recreation of a reality, in the organization and the origin of versions and finally in the interpretation. Any modern historical work refers to them constantly, with the concern of scientific reason, and incorporate them in the body of historical narration, both as documentation and as object of historical evolution. Because the sources do not constitute a "dead museum exhibit" but rather the object that the historian has to structure and process in order to transform it into "history".