The chapter uncovers the role that Grotius’ philosophy of virtues plays in defining and renegotiating the sphere of law in peace; its distinct roles during and after war; the conditions in which Grotius used virtues as a benchmark to correct and evolve law; and the conditions in which he thought that law can rightfully ignore the calls of virtue. Grotius’ function for virtue in law is then compared to conventional roles assigned to religion in correcting and stimulating law. The chapter brings out the coherence of Grotius’ theory of virtue and law as he applied it to diverse real-life problems and themes, ranging from Iberian-Dutch encounters through his justification of free trade to the doctrinal minimalism that Grotius regarded as the best chance of saving the United Provinces from religious strife. The distinctive rights and duties of sovereigns, magistrates, soldiers, slaves, citizens and Christians are finally explained in light of Grotius’ virtue - law dynamic.

Vattel’s influence on the American Revolution is often mentioned but rarely discussed in detail. Most historians of the American Revolution do not consider him at all. Those who do, in a routine gesture ‘piously transmitted’,1 invoke one of the most memorable vignettes in the history of international law: Charles W. F. Dumas (1721–1796) sending three copies of Le droit des gens to Benjamin Franklin (1706–1790) in 1775. In a 9 December 1775 letter, Franklin thanked Dumas and assured him that the copies ‘came to us in good season, when the circumstances of a rising state make it necessary frequently to consult the law of nations’ and the copy assigned to Congress ‘has been continually in the hands of the members of our congress, now sitting’.2 Franklin gave the other two copies to the Library Company of Philadelphia and Harvard College.