The first major study of Scottish hillforts was undertaken by General William Roy and published as The Military Antiquities of the Romans in Britain in 1793. However, Roy only recorded forts like Burnswark with a close relationship to Roman constructions or which he wrongly attributed to be Roman in origin. George Chalmers' (1742–1825) first volume of Caledonia (1807) contained an arbitrary list of forts, but recognised that defences at Burnswark were not just in anticipation of Roman invasion, but to defend against native threats. He also recognised some of the relationships between major and subordinate sites, and the importance of intervisiability between sites. The first serious field research was undertaken in the 1880s and 1890s by David Christison.