Cession of Kuwait, 1913: Wiki

The Anglo-Ottoman Convention of 1913 was a short-lived agreement signed in July 1913 between the Ottoman sultan Mehmed VI and the British over several issues. However it was the issue over the status of Kuwait that came to be the only long-lived result, as its outcome was formal independence for Kuwait.
During the first World War, the Ottoman Empire was financially crippled and the invading British forces invalidated the Anglo-Ottoman Convention, declaring Kuwait to be an "independent sheikdom under British protectorate."