As we can see during the last years thematic cultural portal and digital libraries cover a fundamental role concerning the preservation, managing and fruition of digital cultural resources.

In this scenario the most important aspect regarding the use of metadata and semantic language for the definition of cultural resources: thanks to the metadata and metadatation we are able to define in a unique and interoperable way some different resources and thanks to the use of RDF and SKOS format we are able to integrate them with other information in order to organize knowledge and develop a semantic net of different information.

In this sense, the case of study will be introduced is represented by the portal of italian culture: CulturaItalia.

CulturaItalia is a project coordinated by the Italian Ministry of Cultural Heritage and Activities and as been officially presented on April 2009. The principal purposes of the project regarding the possibility by the users to access to different data sources and guarantee with OAI-PMH protocol data harvesting from different content provider in order to manage and store cultural records. The metadata management is characterized by a specifically Application Profile based on Dublin Core (PICO AP) able to describe both digital and physical resources concerning to the whole cultural heritage domain and by a SKOS thesaurus defined in order to describe the Italian cultural domain and to give a hierarchical order to the resources available into Index of CulturaItalia.

The PICO AP supports some encoding schemes, such as international standard and thesauri or ontologies moreover, the formalization of a specific thesaurus, guarantee the complete interoprability thanks to the SKOS format developed by W3C consortium.

This paper present the new version 4.3 of PICO thesaurus and the entire workflow of definition of conceptual schema and “skossification” of the terms and the integration with PICO AP and PICO thesaurus for the indexing of records. The presentation will be focused furthermore on the problems found during the entire process and on the solution adopted concerning the development of SKOS/RDF structure.