The one-day workshop “Thesaurus building – Introducing TheMaS a tool for multilingual thesaurus building” took place in Athens (Greece), on Friday, 17 March 2017, at the Academy of Athens. The workshop was organized by the Academy of Athens within the framework of DARIAH-EU project “Humanities at Scale”. The topic of the workshop was “Building Multilingual Thesauri” and it focused on the presentation of the Greek web tool TheMaS (Thesaurus Management System), which was developed within the framework of DARIAH-Gr project. TheMaS is an open source Web based system for creating, managing and administering multi-faceted multilingual thesauri. The workshop was intended for the humanistic scientific community and for educational, scientific and cultural heritage institutions (galleries, libraries, archives and museums) to which thesauri are necessary not only for the organization of knowledge and information in general but also they are an important factor in ensuring the sustainability of e-infrastructures.