The aim of the talk is to present the methodology used to reorganise the PACTOLS thesaurus of Frantiq, launched within the framework of the MASA consortium. PACTOLS is a multilingual and open repository about archaeology from Prehistory to the present and for Classics. It is organized into six micro-thesaurus at the root of its name (Peuples, Anthroponymes,Chronologie, Toponymes, Oeuvres, Lieux, Sujets). The goal is to turn it into a tool interoperable with information systems beyond its original documentary purpose, and usable by archaeologists as a repository for managing scientific data. During the talk, we will describe the choice of tools, the organisation of work within the steering group and the collaborations with specialists for the upgrading and development of the vocabulary while showing the strengths and limitations of some experiments. Above allit will show how the introduction of the conceptual categories of the BackBone Thesaurus of DARIAH, modelled on the CIDOC-CRM ontology, through a progressive deconstruction/reconstruction process, eventually had an impact on all micro thesauri and questioned the organisation of knowledge so far proposed.