The question of 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 gain importance on a global scale. This chapter discusses the history of the law of the sea from the perspective of ‘Renaissance Europe’, focusing 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). It shows that the concept of the free sea was perfectly compatible with the adjacent or territorial sea both in legal practice and in 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 between Spain and Portugal based on the papal bull Inter Caetera (1493) and the treaties of Tordesillas (1494) and Zaragoza (1529).

This chapter studies how the ocean became a realm of human rights aspiration. It illuminates the emergence of an oceanic idea of human rights as an antislavery work, the invention of African Americans who had been held as slaves as well as of freeborn abolitionists. In antislavery thought, the ocean constituted not a space for traversing, creating wealth, or making war – of commerce and of empire – but a realm of natural human liberty. The chapter traces the origins of this idea to a slave rebellion aboard an American ship sailing on the Atlantic ocean in 1841– a coastwise slave trade voyage– and the conflict of laws caused by the rebellion. Out of this conflict, the chapter argues, emerged emancipatory doctrine that contributed to a burgeoning antislavery invocation of human rights while transforming a conception of the free sea that was centuries old.