In this chapter, I try to delve into the history of the laws of armed conflict from a materialist approach. Initially, I try to explain the importance of materialist way of doing history and the metaphor of base and superstructure. In this chapter, I draw a picture of a period from the sixteenth century to the first half of the nineteenth century. My focus is on the rules of war suggested by Francisco de Vitoria, Hugo Grotius and other European writers, emerging colonization and growing capitalism. I mainly engage with the political economy of that time to explain how colonization and growing capitalism shaped the warring tendencies of the European nations and their conduct during war. The chapter underlines that the rules of war were not so developed during this period, but this era does reveal how the political and economic realities of the time led to militarism and shaped the attitude of powerful countries towards regulation of conduct during war. The Battle of Plassey, Napoleonic Wars and Crimean War explain this position. In this way, this chapter prepares the necessary background for the next chapter.