The CIPHER project aims to develop the tools and methodology required for Cultural Heritage Forums - online spaces for the active exploration of cultural heritage. Within the project, knowledge technologies are being developed to provide intelligent support for Cultural Heritage Forum users. Here we outline the CIPHER Knowledge Framework, that specifies how CH Forum content can be formally described in order to support desired services. The CIPHER Knowledge Framework incorporates four types of description: (i) the naming of collected heritage objects identified as belonging to the associated heritage domain; (ii) the interpretation of heritage objects according to ontologies of the domain; (iii) the formal representation of stories, their structure and content; and (iv) the formal representation of narratives and their components. The CIPHER Knowledge Framework is motivated by theories of creativity, story construction and narrative. It is intended that the CIPHER Knowledge Framework will support story construction by CH Forum members, exploration of forum resources, and the personalised presentation of forum content.