Portrait of a man from Jeddah c. 1918. Taken before the Saudi conquest of Hejaz, this picture was technically in the Hashemite Kingdom of Hejaz.
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The Kingdom of Hejaz was a state in the Hejaz region (western portion of the Arabian Peninsula) that was ruled by the Hashemite dynasty. It was self-proclaimed in June 1916 during the First World War, as independent from the Ottoman Empire based on an alliance with the British Empire to drive the Ottoman Army from the Arabian Peninsula during the Arab Revolt.
The United Kingdom promised King Ali of Hejaz a single independent Arab state that would include modern-day Iraq, Jordan, Palestine, and Syria in addition to the Hejaz region. However, at the end of the First World War, the Treaty of Versailles turned Syria into a French mandate and Iraq, Palestine and Transjordan into British mandates.
Relations with the British Empire further deteriorated when European Zionists were allowed to move to Palestine. Hussein refused to ratify the 1919 Treaty of Versailles and, in response to a 1921 British proposal to sign a treaty accepting the Mandate system, stated that he could not be expected to "affix his name to a document assigning Palestine to the Zionists and Syria to foreigners." A further British attempt to reach a treaty failed in 1923–24, and negotiations were suspended in March 1924; within six months, the British withdrew their support in favor of Abdulaziz Ibn Saud, who proceeded to conquer Hussein's kingdom.