Hugo Grotius

Hugo Grotius or Hugo de Groot (1583-1645) worked as a jurist in the Dutch Republic. In his book Mare Liberum (English: Free Seas) he formulated a new principle, claiming that the sea was international territory and all nations were free to use it for seafaring trade. England, competing fiercely with the Dutch for domination of world trade, opposed this idea and claimed sovereignty over the waters around the British Isles.

The dispute had important economic implications. The Dutch Republic supported the idea of free trade (even though it imposed a trade monopoly on nutmeg and cloves in the Moluccas). England adopted the Act of Navigation (1651), forbidding any goods from entering England except on English ships. The Act subsequently led to the First Anglo-Dutch War (1652 - 1654).

Grotius also laid the foundations for international law regarding matters of conflicts between nations in his book De iure belli ac pacis (English: About laws of war and peace).

Grotius ranks as one of the founding figures of International law.