A computer-implemented system and method for processing a markup language document and its change history are provided. The method includes receiving first and second versions of the same target document into computer memory. One of the first and second versions of the target document is encapsulated within an encapsulating document. A change history corresponding to a difference between the first version and the second version of the target document is encoded. The change history is encapsulated within the encapsulating document. The encapsulated document can then be output. As each new version of the target document is created, the encapsulating document can be modified to reflect the changes, enabling prior versions of the target document which have been encapsulated to be extracted at any time.