Mare clausum

Mare clausum (legal Latin meaning "closed sea") is a term used in international law to mention a sea, ocean or other navigable body of water under the jurisdiction of a state that is closed or not accessible to other states. Mare clausum is an exception to mare liberum (Latin for "free sea"), meaning a sea that is open to navigation to ships of all nations.^[1]^[2] In the generally accepted principle of international waters, oceans, seas, and waters outside national jurisdiction are open to navigation by all and referred to as "high seas" or mare liberum. Portugal and Spain defended a Mare clausum policy during the Age of Discovery.^[3] This was soon challenged by other European nations.

^ Robert McKenna, "The Dictionary of Nautical Literacy", p. 225 McGraw-Hill Professional, 2003, ISBN 0-07-141950-0
^ Gabriel Adeleye, Kofi Acquah-Dadzie, Thomas J. Sienkewicz, James T. McDonough, "World dictionary of foreign expressions: a resource for readers and writers", p. 240, Bolchazy-Carducci Publishers, 1999, ISBN 0-86516-423-1
^ The licensing of vessels by the Portuguese was initiated by Prince Henry the Navigator in 1443, after Prince Pedro granted him the monopoly of navigation, war, and trade in the lands south of Cape Bojador. Later this law would be enforced by the bulls Dum Diversas (1452) and Romanus Pontifex (1455); more bulls and treaties followed, the most significant being the Treaty of Tordesillas.

[1] Robert McKenna, "The Dictionary of Nautical Literacy", p. 225 McGraw-Hill Professional, 2003, ISBN 0-07-141950-0

[2] Gabriel Adeleye, Kofi Acquah-Dadzie, Thomas J. Sienkewicz, James T. McDonough, "World dictionary of foreign expressions: a resource for readers and writers", p. 240, Bolchazy-Carducci Publishers, 1999, ISBN 0-86516-423-1

[3] The licensing of vessels by the Portuguese was initiated by Prince Henry the Navigator in 1443, after Prince Pedro granted him the monopoly of navigation, war, and trade in the lands south of Cape Bojador. Later this law would be enforced by the bulls Dum Diversas (1452) and Romanus Pontifex (1455); more bulls and treaties followed, the most significant being the Treaty of Tordesillas.

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