João Pedro Ribeiro is one of the scholars that perform the labor proposed by the Sciences Academy of Lisbon to prepare the written of a Portuguese history between the Eighteenth Century and the Nineteenth Century. He searches and chooses documents which he judges necessary for this task, guiding the later historical works. I also work with the Portuguese Enlightenment and the formation that makes this kind of project possible. Then, I discuss the growing importance of the concept of history since the second half of the Eighteenth Century, as well as the occurrence of changes in this concept. My work also lays emphasis on the disputes about a disciplinary memory that chooses Ribeiro as the pioneer and precursor for Portuguese diplomatics and paleography.