侯赛因·本·阿里
In November 1917, Philby was sent to the interior of the Arabian Peninsula as head of a mission to Ibn Saud, the chieftain who professed Wahhabism, the movement within Sunni Islam, and a bitter enemy of Hussein bin Ali, Sharif of Mecca, who led the Hashemites and the Arab Revolt, who were both contenders for "King of the Arabs". Philby secretly began to favour Ibn Saud even though British policy supported Sherif Hussein. Philby completed a crossing from Riyadh to Jeddah by a "backdoor" route to demonstrate that Saud, not Hussein, was in control of the Arabian highlands.