"Dear Henry McMahon, just received your letter about the Arab Revolt. Excited to work together to kick out the Ottomans! #ArabRevolt #LetTheGamesBegin - Hussein bin Ali, Sharif of Mecca"
Jul 14, 1915 - Beginning of the McMahon–Hussein Correspondence between Hussein bin Ali, Sharif of Mecca and the British official Henry McMahon concerning the Arab Revolt against the Ottoman Empire.
https://en.wikipedia.org/wiki/McMahon%E2%80%93Hussein_Correspondence