The Draft Core Data Standard For Archaeological And Architectural Heritage was published in 1995 and has now been revised in the light of practical experience and new theoretical insights.
This paper reviews the changes that have been made in theory, content and style. The new standard has also been mapped to a number of other standards, most recently the CIDOC Conceptual Reference Model. Observations on the process of making these mappings and the results are also included.
Finally the paper will present examples of how the new standard can be used to construct powerful mechanisms for explaining the past.

Keywords: CRM, Interoperability, CIDOC, CDS