Anet is a network of scientific libraries located in Antwerp, Belgium. Among the connected institutions are research, higher education and museum libraries. In 2014 was decided to adopt a new subject heading system for cataloging the library collections with an art or heritage scope. The Art & Architecture Thesaurus® (maintained by the Getty Research Institute) was eventually selected, under the express condition that it can be used in a flexible way by the libraries. The local subject heading systems (terminologies) were converted to the new authority environment (Anet-AAT). Manual mapping was performed because of the different application as subject heading system and the opportunity to acquaint the librarians with AAT. Future challenges for the Anet-AAT vocabulary consist of staying updated with changes that occur in the ‘Mother AAT’ (Getty Vocabularies) and adding to its content to create more library specific subjects - AAT is presently quite focused on the description of (museum) objects. The content pf ATT is quite well suited for indexing the special libraries. Nevertheless, the usage by the network did bring to light issues in the structure of AAT, particularly some concerning the Dutch translation. The necessity to address these issues has resulted in regular contacts between Anet and the RKD-Netherlands Institute for Art History that manages the Dutch translation of the AAT. The adaptation of AAT by Anet has proven to be a promising showcase for the potential of this ‘museum thesaurus’ as a subject heading system for libraries as well.