After setting out the importance of the notion of an international community in contemporary treaties, International Court of Justice judgments and opinio juris, this paper claims that we need to turn to Cicero's works in order to appreciate a sense of what an international community is. Cicero was the first jurist known to recognize and elaborate a theory of the international community and this through his concept of jus gentium. Cicero's theory of jus gentium, I argue, was neither a positivist theory nor a natural law theory. Instead, jus gentium dwelt in an intermediate position between posited state laws and the laws of nature. I find a problem, however, in that Cicero exempts certain types of society from the guidance and protection of the jus gentium. I document examples of the sort of society so exempted. In order to understand why Cicero exempts such societies from the protection of the jus gentium, I argue, Cicero's theory depends on a primordial condition where human beings, living an animal-like existence, lack a language and reason. Cicero posits that human beings must leap from such a primordial condition into a civilized world where language is shared. Cicero associates a civilized world with communication, deliberation, reason, and law, particularly the jus gentium. His theory of jus gentium thereby hierarchizes societies and begs that we ask whether such a hierarchy remains presupposed in contemporary international law and international legal theory.