The BackgroundHugo Grotius (1583-1645) was endowed with remarkable gifts. He shone as a humanist scholar, a poet, and a historian. He was an expert theologian and a leading politician in his native Holland, and in these capacities actively involved in the theological and political conflicts in the Netherlands of his time. He was also preeminent in the legal profession, served in various public functions, and was the author of a work that became the standard text on Dutch jurisprudence. What will be discussed in this paper, however, is yet another achievement of his, the work that earned him the appellation father of international law. De jure belli acpacis libri tres (Three books on the law of war and peace), was published in 1625 in Paris, where he lived in political exile.1The work obviously met a need: a number of editions to which corrections and amendments of his were added had already been published in his lifetime, and subsequently there were even more. Jean Barbeyrac (1674-1744) recorded that it did not take long before an edition (Frankfurt a.d.O., 1691) cum commentants variorum, was published. This, he remarked, was an unusual honor: the authors of classical antiquity had to wait many centuries before their works were so edited. But then, as he writes, Jamais livre n'eut une approbation plus universelle.2 Barbeyrac, incidentally, deserves a brief introduction. He was a refugee from the persecution of Protestants in his native France and became a professor first in Lausanne and from 1717 in Groningen. He published an edition of Grotius's De jure and translated into French the major works on natural law by Grotius, Pufendorf, and Cumberland, which he supplied with wide-ranging prefatory discourses and copious annotations. He was the most frequent contributor to the monthly periodical Bibliotheque raisonnee?By the end of the seventeenth century, a new genre of writing emerged: histories of morality.4 This historiographical trend had its modest beginning with Samuel Pufendorf's (1632-94) short historical sketch on the origin and progress of the discipline of natural law.5 It presented Grotius as laying the foundation for this new discipline. Pufendorf saw himself as continuing what Grotius had begun. In the early eighteenth century, Barbeyrac and others, like Thomasius (1655-1728) and Buddeus (1667-1729) maintained that what Grotius had done was comparable to what Copernicus, Galileo, Bacon, and Descartes had done for natural philosophy.In the Prolegomena (i.e., the prefatory discourse) to his magnum opus, Grotius explained his main guiding principles, the sources and authorities he would rely on, and so on. His theory rests on ancient, especially Stoic and Christian traditions. They include the idea that there are binding norms of justice and morality, valid for all mankind equally. These higher norms ought to govern conduct even if they are not everywhere acknowledged or observed. They are valid even in the absence of an established authority able or willing to enforce them. That promises should be kept, that nobody should be harmed, that one should refrain from taking that which belongs to another, are among these norms.The very notion of international law, which Grotius wanted to promote, depends on the assumption that there are such higher norms of justice and morality. It is, he notes, an assumption that has been doubted or denied by many, who argue that such norms are illusory and that, even if they are valid, it would be sheer folly to heed them. At the outset it is therefore appropriate for him to show that they are mistaken, and this is what he undertakes in the early sections of the Prolegomena. Since those whose opinion he wants to refute are so many (turba, a crowd, a multitude)6 he appoints one advocate for them all, the ancient philosopher Carneades (216-129/8 BC)-the reason for this choice will be discussed farther on-who became scholarch of the Academy in Athens and was seen as a renewer of the sceptical tradition that Arcesilaus had founded. …