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Hugo Grotius' 'Mare Liberum' – 400th anniversary

There are few individuals that have shaped international law as much as Hugo Grotius, the Dutch jurist, diplomat and philosopher, theologian and poet. His works include a comparison of constitutions (Parallelon rerumpublicarum), commentary on the law of prize and booty, a thesis on the free seas (Mare Liberum), a thesis on the law of war and peace (De jure belli ac pacis) and commentaries on both the old and new testament (Annotationes in Vetus Testamentum and Annotationes in Novum Testamentum). Whereas the work on the law of war and peace – with the suggestion of the theory of just war and the division between jus ad bellum and jus in bello – is the one for which he is most known, the Mare Liberum for numerous reasons is just as remarkable as any of his other works. Written when Grotius was merely 26 (!) years of age, Mare Liberum was not only an important work from a legal perspective but it was also a thesis with an important political statement.

In 1604 Grotius was asked by the Dutch East India Company to draft a defence of a seizure of a Portuguese carrack by a captain belonging to the Company. At this time, the Dutch were at war with both Spain and Portugal (the Eighty Years’ War) and it was a conflict that was to a large extent fought at sea. The thesis Grotius produced between 1604-1605 (De Indis) was longer and more detailed than anybody expected and dealt with numerous issues that later were going to form the foundation for Grotius’ most famous works. One chapter in fact later became the influential pamphlet Mare Liberum.

In this work Grotius described the principle that the sea was an international territory and that all nations were free to use it for seafaring trade.

My intention is to demonstrate briefly and clearly that the Dutch—that is to say, the subjects of the United Netherlands—have the right to sail to the East Indies, as they are now doing, and to engage in trade with the people there. I shall base my argument on the following most specific and unimpeachable axiom of the Law of Nations, called a primary rule or first principle, the spirit of which is self-evident and immutable, to wit: Every nation is free to travel to every other nation, and to trade with it.

The principle inter alia provided the basis for the breaking up of the trade monopolies that had existed so far. However, motivated by the political realities of the time, numerous counter arguments were put forward in the years following the publication of Mare Liberum, among them the thesis ‘An Abridgement of All Sea-Lawes’ (1613) by William Welwod (a Scottish jurist) and ‘Mare clausum’ (1635) by John Selden.

UNCLOSToday the law of the sea is primarily governed by the UN Convention on the Law of the Sea (UNCLOS; today signed by 159 parties [158 States and the EC]), which to a large extent is a codification of the customary international law of the sea. Whereas the UNCLOS does incorporate the idea of a specified belt of water extending from a nation’s coastline (the idea of a country’s territorial waters, which form part of that State’s sovereign territory, is ultimately based on thoughts by John Seldon), beyond this coastline the waters are considered international waters that are free to all nations, but belonging to none of them – just as Grotius had suggested 400 years ago.

The whole Mare Liberum (with an introductory note by James Brown Scott) is available online. In celebration of the 400th anniversary of the publication of Mare Liberum various institutes are organizing events in The Hague, check out the organizers’ website here.

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