 All peoples created regimes: since a multitude could not govern itself well, power was entrusted to a group or individual acting for the common good. The best regime, in Vitoria’s opinion, was rule by one person, who was both above the community and within it. Individuals might even sacrifice their lives in defense of the common good. Society’s natural purpose, the preservation of temporal life of its members, was not in contradiction to the Church’s end: the salvation of souls. In a Christian commonwealth, salvation was the primary purpose, with human felicity as the secondary end. The commonwealth transferred its power to the ruler, but his power ultimately derived from God; and after its transfer of power to the ruler, the commonwealth ceased to be able to legislate. Since the ruler was within the commonwealth, he was bound by its laws. Vitoria states that monarchy is the best form of government, but insists that a whole commonwealth may be punished for the sins of its king, if he, for example, wages an unjust war against another prince (ibid., qu. 1 art. 8–9). This commonplace among the theorists of the ius gentium was important for some of the justifications of slavery and the slave trade, because captives in a just war traditionally became slaves and because the punishment of a whole commonwealth decided the fate of all its members, regardless of their individual guilt or innocence.