This is a history of and a technical report on the Charles Harpur Critical Archive (CHCA), which has been in preparation since 2009. Harpur was a predominantly newspaper poet in colonial New South Wales from the 1830s to the 1860s. Approximately 2700 versions of his 700 poems in newspaper and manuscript form have been recovered. In order to manage the complexity of his often heavily revised manuscripts, traditional encoding in XML-TEI, with its known difficulties in handling overlapping structures and complex revisions, was rejected. Instead, the transcriptions were split into simplified versions and layers of revision. Markup describing textual formats was stored externally using properties that may freely overlap. Both markup and the versions and layers were merged into multi-version documents (MVDs) to facilitate later comparison, editing and searching. This reorganisation is generic in design and should be reusable in other editorial projects. Keywords Charles Harpur. Romanticism. Digital archive. Multi-version documents (MVDs). XML-TEI. Standoff markup 1 Background This is a history and a technical report on the Charles Harpur Critical Archive (CHCA). Looking back to its beginnings in 2009, it is clear that we did not fully appreciate the size and nature of the challenge that lay ahead. Funding from the Australian Research Council paid, initially, for data input and research assistance. The development of the