Mare liberum, mare clausum en de territoriale wateren: Doctrine en context van het zeerecht in de late middeleeuwen en de vroegmoderne tijd

The question whether or not the sea can be owned or controlled has occupied the minds of many over the centuries. The discovery of America by Columbus made the questions of ownership of the sea and how regimes to govern the sea could be created and managed gaining importance on a global scale. The historiography of the law of the sea is mostly focussing on the ‘battle of the books’ dominated by the publication of Mare Liberum (1609) by Hugo de Groot (Grotius) and John Selden’s Mare clausum (1635). This article puts this debate in its wider temporal, that is medieval context by arguing that the concept of the free sea was perfectly compatible with the adjacent or territorial sea both in legal practice and principle. The idea of the free sea, defended and made explicit by Grotius, was not new but originated in Roman law and its medieval interpretations. Rather than the free sea, mare clausum was the new contribution of early modern thinking on the law of the sea. The concept of mare clausum had been shaped by the division of the world’s oceans among Spain and Portugal based on the papal bull Inter Caetera (1493) and the treaties of Tordesillas (1494) and Zaragoza (1529).