This chapter outlines relevant rules and concepts of international investment law, international humanitarian law, international human rights law as well as customary international law that are relevant to the protection of foreign investments during armed conflict. This includes also identification of issues imbued within selected standards of protection that are discussed in the doctrine and/or highlighted in the context of conflict-related scenarios. This concerns, for example, the nature of due diligence obligations of host States facing armed conflict, the relationship between war clauses and other investment treaty standards or the legality of targeting of critical civilian infrastructure. After describing selected relevant rules within each of the applicable fields, the author applies these rules to practical examples, referring to relevant arbitral practice concerning conflict-related claims. Modelling of scenarios in the previous chapter for better-tailored application of the relevant legal framework allowed the author to identify and conceptualize pertinent legal issues to be addressed in subsequent chapters. This concerns the question of application of investment treaties to occupied territories and normative interactions and possible conflicts between applicable rules from different fields.