Chapter 1 looks at the historical development of IHL, from its origins in Europe in the 1850s, and the historical events that have shaped the law through the last century and a half. It describes the effect of the Battle of Solferino in 1861 on Henri Dunant, leading to the founding of the International Committee of the Red Cross in Geneva, as well as the parallel development of the Lieber Code arising out of the American Civil War. The core treaties and other instruments forming the basis of modern IHL are outlined, from the 1864 Geneva Convention to the more recent development of international criminal law and its contribution to the law of armed conflict

Until quite recently, international relations theory neglected the role of emotions. This chapter surveys the rehabilitation of emotions and moral sentiment in political and international relations theory with a view to examining the cultivation of sympathy as a normative and historical condition of international humanitarian law as a ‘civilising process’. The chapter argues that, as part of a broader ‘civilising process’ to alleviate unnecessary human suffering, moral sentiment has been an indispensable, if ambivalent, factor in the historical pursuit of humanitarian action. The chapter argues that the modern codification of international humanitarian law is predicated on the cultivation of moral sentiments such as sympathy and compassion being extended to those injured or killed on the battlefields.