This thesis analyses the use and abuse of ‘foreign’ soldiers in the political rhetoric of the Lower-Rhine-Westphalian Circle between 1576 and 1618, exploring what the categorisations applied to such men can tell us about warfare and identity in the Holy Roman Empire and beyond. It argues that the Imperial approach was characterised by nuance, flexibility, and constructive ambiguity, which allowed the region to avoid being drawn deeper into conflicts to which there was no military solution. A key reason for its success was that – despite a profusion of patriotic language denouncing foreign threats – when it came to translating rhetoric into political practice, troops were judged primarily by their profession rather than their origins. As a result, the region’s engagement with soldiers featured more continuity than either radical reform or destabilising decline. These points are demonstrated using analysis aimed at three different levels of the Reich’s constitutional order; the Empire as a whole, local territorial principalities, and – crucially – the regional Imperial Circles which connected the other two. In Part I, the Lower-Rhine-Westphalian Kreis is examined as a forum for discussion, as a military employer in its own right, and as a borderland area alongside the neighbouring Burgundian Circle. In Part II, three representative case-studies drawn from individual Circle Estates highlight in greater depth the ways in which local authorities and commentators learned to adapt successfully to the presence of outside forces. Finally, Part III describes how Lower-Rhine-Westphalia’s experiences played out within the formal and informal networks which bound together the entire Reich.