This chapter examines the eighteenth-century British army and the contexts in which it operated at home and abroad. It considers the ways in which the laws of war, and common European values and understandings, influenced the British army. The chapter argues that whilst the primary role of the army remained constant throughout the century, its purpose evolved in light of imperial expansion and the military enlightenment. This led to the professionalisation of the institution and, under the Duke of Cumberland, increased the army’s influence on domestic, foreign, and imperial policy. At the same time, domestic resistance to a standing army lessened as that army increasingly played a visual role as a defender of the empire and a civilising force, although civil-military tension remained common, particularly in places where the loyalty of the populace was considered suspect.