The first chapter offers a comprehensive analysis of the history and development of the law of armed conflict (LOAC), emphasizing the formulation of legal principles that regulate warfare. The chapter examines the historical backdrop of LOAC, tracing its origins from early codifications in the nineteenth century and the Geneva and Hague Conventions to modern frameworks. This basic discourse elucidates the contrast between jus ad bellum (the right to use force) and jus in bello (the regulations governing conduct during the use of force), highlighting the practical and ethical intricacies of applying the LOAC norms. The author emphasizes and examines previous literature on the principle prohibiting superfluous injury or unnecessary suffering (SIrUS) and its applicability to limiting the means and methods of warfare. The author introduces the operation of other related customary LOAC principles, such as proportionality, necessity, and humanity, within the framework of LOAC. The chapter sets up a foundation for examining the evolution of SIrUS with changes in military technology and international standards regarding the conduct of hostilities for a subsequent in-depth examination of the application of LOAC and SIrUS in contemporary armed conflicts.