The esoteric law of the sea – commerce.
For the 17th century Mare liberum and Mare clausum were the centerpieces of the debate between advocates of exclusive and inclusive uses of ocean space. In England, Mare clausum reigned supreme as the authority on all questions of sovereignty at sea, although its authority on more mundane legal issues of maritime law yielded late in that century to Charles Molloy’s De jure maritime et navali, or, A Treatise of Affaires Maritime, and of Commerce (1676), which dealt with mercantile questions such as bills of exchange, insurance and maritime loans.
Neither Welwood nor Selden dealt decisively with the question of how far out to sea a sovereign’s territorial sea could extend: Welwood seemed to suggest one hundred miles, but left the issue open; Selden finessed it entirely. In time, British maritime power rendered such matters moot: as an old saw had it, “Britannia rules the waves – and waives the rules.”
Jordan Maxwell: Maritime Law Rules the World Commerce and Courts