The Nature and Sources of Europe's Classical Law of Nations

26 Pages Posted: 30 Jun 2015

See all articles by Randall Lesaffer

Randall Lesaffer

Tilburg Law School; KU Leuven - Faculty of Law

Date Written: June 25, 2015


The jurisprudence of the law of nature and nations of the Early-Modern Age holds pride of place in the modern historiography of international law. Whereas the classical writers of that age undeniably exercised a significant influence on 19th-century international law, their utility as a historical source for the study of the law of nations from their own period has been far overrated. The development of the law of nations between 1500 and 1800 was much more informed by State practice than historians have commonly credited.

Moreover, historiography overestimates the novelty of the contribution of early-modern jurisprudence and has almost negated its major historic source of inspiration: the late-medieval jurisprudence of canon and Roman law. It is important to restore medieval jurisprudence to its rightful place in the grand narrative of the evolution of international law in Europe. Doing this renders a deeper insight into the dynamics of the jurisprudence of the Early-Modern Age. It shows that natural law acted as a vessel to recycle many of the doctrines of medieval jurisprudence into the language of the early-modern law of nations. But it also shows how it was an altogether feeble attempt at replacing the restrictive authority of scholastic jurisprudence with that of natural justice. As long as the fear of God gave teeth to the precepts of natural justice, it retained some real impact. But one this was lost and 19th-century international lawyers cut the historic bonds between natural law and religion, they pushed it to the wayside and ostracised it altogether from their world.

Keywords: international law, legal history, sources of law

JEL Classification: K33

Suggested Citation

Lesaffer, Randall C. H., The Nature and Sources of Europe's Classical Law of Nations (June 25, 2015). Tilburg Law School Research Paper No. 12/2015, Available at SSRN: or

Randall C. H. Lesaffer (Contact Author)

Tilburg Law School ( email )

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Tilburg, 5000 LE
0031 13 4662294 (Phone)


KU Leuven - Faculty of Law

Tiensestraat 41
Leuven, B-3000

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