Great Britain having bottled up the North Sea, a mare liberum must be established.
Twenty-nine years after her answer to Mendoza, in 1609, appeared Grotius's short treatise "mare liberum."
Selden's Mare clausum was a reply, written by the king's command, to the mare liberum.
So early as in 1609 the great Grotius had published his treatise of mare liberum in favour of the freedom of the seas.
mare liberum, seu de jure quod Batavis competit ad Indica commercia.