Chapter Three relies on the conceptions of dignity introduced in Chapter Two to examine the historical processes through which human dignity found expression in international law, narrating when, why and, most importantly, which conceptions of human dignity permeated international law. The primary objective of Chapter Three is to demonstrate that distinct conceptions from the past (sovereign and human dignity, the latter in its Christian and secularised strands) have permeated debates at the origins of international law, sometimes blending with – and blurring – each other. More specifically, the study identifies three different but intertwined constitutive stages in this formalization process in international law, specifically: (i) a first constitutive stage, spanning from 1850 until 1949 (when the main area of expression of human dignity is international humanitarian law); (ii) a second constitutive stage, from 1919 until 1966 (with rise of international human rights law); and (iii) a third constitutive stage, running from 1899 until 1998 (with the emergence and slow consolidation not only of international crimes but also of international criminal tribunals).