At the Archives Departementales des Pyrenees-Atlantiques, the encoding of more than forty legacy finding aids written between 1863 and 2000 is part of a program of digitization of the collections. Because of the size of the project, an external consultant, ArchProteus, has been brought in and specific management procedures have been put in place within the institution. The conversion has allowed the testing and verification of the flexibility of the EAD DTD, despite the various hurdles negotiated throughout the project, such as the necessity of reengineering finding aids, and standardizing index terms, etc. It becomes clear that a conversion project--in this case, a retrospective conversion--will lead the archivist to rethink the production of finding aids and the relationship with users and patrons. (Contains 3 tables and 4 notes.)