This paper will describe the creation of an ontology to model information contained in historical documents. It will describe the structure of the RDF/OWL ontology and how the model facilitated the expression and analysis of implicit and hidden information/associations existing in the sources. Some aspects of data processing and delivery based on the ontology, like the generation of indices and the implementation of search mechanisms, will also be described. Key words: Ontologies, RDF/OWL, authority lists, indices, search, medieval documents, family history, career study, Henry the III.