Final answer:
Mare Liberum, a different text from The Liberator, was written by Hugo Grotius and first published in 1609.
Step-by-step explanation:
The document Mare Liberum (Freedom of the Seas) is often confused with The Liberator, an abolitionist newspaper published by William Lloyd Garrison. However, Mare Liberum is a different text altogether, written by the Dutch jurist and philosopher Hugo Grotius. It was first published in 1609, advocating for free trade and the use of the seas for all nations. While Garrison's The Liberator, started in 1831, contributed significantly to the antislavery movement, Hugo Grotius's Mare Liberum laid the foundation for international law concerning the open seas. Although the provided references mention various other historical events and documents, they do not contain information about the publication date of Mare Liberum.