In this paper we present the basic requirements and initial design of a system which manages and facilitates changes to an OWL ontology in a multi-editor environment. This system uses a centralized client-server architecture in which the server maintains the current state and full history of all managed ontologies. Clients can access the current ontology version, all historical revisions, and differences between arbitrary revisions, as well as metadata associated with revisions. This system will enable many other ontology based services, such as incremental reasoning, collaborative ontology development, advanced ontology search, and ontology module extraction. Taken holistically, this network of services will provide a rich environment for the development and management of ontology based information systems. 1 Motivation and Requirements We need for a system that manages access to a changing ontology. This requirement is experienced by a variety applications with different stakeholders...