Abstract. In this paper we describe the work that was done in the Corporate Ontology Grid (COG) project on the querying of existing legacy data sources from the automotive industry using ontology technology and a conceptual ontology query language. We describe the conceptual ontology query language developed by Unicorn, the querying support provided by the Unicorn Workbench, and describe the use of these queries in the run-time architecture built in the COG project.