The London Straits Convention re-establishes the "ancient…
July 1841 CE
The London Straits Convention re-establishes the "ancient rule" of the Ottoman Empire by closing the Turkish straits of Bosporus and the Dardanelles, which links the Black Sea to the Mediterranean, from all warships whatsoever, barring those of the Sultan's allies during wartime.
It thus benefits British naval power at the expense of Russian as the latter lacks direct access for its navy to the Mediterranean.
Concluded on July 13, 1841 between the Great Powers—Russia, the United Kingdom, France, Austria and Prussia—the treaty, the latest in a series dealing with access to the Bosporus, the Sea of Marmara, and the Dardanelles, had evolved from the secret Unkiar Skelessi of 1833, in which the Sublime Porte had guaranteed exclusive use of the straits to "Black Sea Powers'" (i.e., the Ottoman Empire and Imperial Russia) warships in the case of a general war.