Museum documentation can be distinguished into administrative and cultural. In the first case, the interest is focused on administrative information, regarding the conservation and control of the state and position of objects, as well as the organization of exhibitions, while in the second on historical and cultural information, regarding the creation. technique, style, etc., of objects, as well as relationships with other objects, persons and historical events. This thesis is about CLIO, a cultural documentation system. CLIO is used as a scientific catalog and can include all the information which constitutes the current knowledge about a group of objects organized by collections or by subject. The information consists of structured descriptions organized in a knowledge base according to a semantic ontological model, implemented in the TELOS language, and multimedia data (images, sound, text). The CLIO ontology includes notions of matter, location, occurrence, measurement, mankind, conceptual creation and naming, and their interrelationships. During the model development we dealt with specific problems of representation of space and time, spatial and temporal relationships, measurement, part and membership relations, ambiguity and contradiction of the existing information, description of default attributes, names and synonyms, nd indication of the source of historical information. To illustrate its application, the basic model was specialized for the documentation of Cretan and Byzantine Pots and of Greek folk garments from the collection of the Historical Museum of Crete. The operational kernel of CLIO is the Semantic Index System (SIS), developed at the Institute of Computer Science, Foundation of Research and Technology-Hellas, in order to enhance the efficiency of user dialogs of CLIO, a set of predefined queries was developed, taking into consideration the basic notions and their interrelationships. The queries are specialized for cultural documentation, yet general enough to be used in both demonstrator applications. An important problem, which was studied, is view definition in a semantic data model. A view mechanism consists in presenting an abstraction or part of the schema or the data. A survey of models concerning grouping and abstract representation of entities, as well suggestions for the design of a view mechanism for CLIO are given.