Catalogues are the core documents of museum structure and meaning. Yet no significant computational analysis has been made of how catalogues from the early modern period are constructed or of the way their structure and content relate to the world from which collections are assembled. The Leverhulme-funded ‘Enlightenment Architectures: Sir Hans Sloane’s catalogues of his collections’ (2016–19), a collaboration between the British Museum and University College London, with contributing expertise from the British Library and the Natural History Museum, seeks to change this. The Enlightenment Architectures project is analysing Sloane’s original manuscript catalogues of his collections to understand their highly complex information architecture and intellectual legacies. In this article we explore some of the challenges of seeking to integrate the methods of digital humanities with those of cataloguing, inventory, curatorial and historical studies and of bringing such interdisciplinary approaches to bear on early modern documentary sources. We do this through two case studies that highlight the approaches to encoding Sloane’s catalogues in TEI that Enlightenment Architectures has employed and the major challenges that these have brought to the fore.