Britannica Sources used in this answer

How did Mare Liberum argue for freedom of the seas?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Oil portrait of Hugo de Groot, also known as Hugo Grotius, by the workshop of Michiel Janszoon van Mierevelt, showing him with a ruffled white collar and dark clothing. — Hugo Grotius Portrait of Hugo de Groot (Hugo Grotius), oil on panel by the workshop of Michiel Janszoon van Mierevelt, 1631; in the Rijksmuseum, Amsterdam.

In his influential work Mare Liberum (1609), Hugo Grotius argued that the sea is international territory that should remain open to all nations for navigation and trade.1

He developed this position to challenge the claims of Spain and Portugal, which sought to enforce a monopoly on trade with the East Indies by asserting territorial sovereignty over the oceans. Grotius contended that these monopolies deprived other nations of their natural right to trade. By defending free access to the ocean, he provided a legal foundation for the Dutch East India Company to operate in contested waters, effectively arguing against the concept of private or national ownership of the high seas.1

This work is considered a foundational text in the development of international law, as it helped establish the principle that the seas are a common resource rather than the property of any single power.12