The first Caliph from the House of ‘Ali ibn Abi Talib since al-Hasan ibn ‘Ali (d.670), and first Arab-Hashemite Caliph since the fall of the Abbasid Caliphate in 1258; His Exalted Highness Sayyid Hussein bin Ali, GCB, the Sharif of Mecca, Emir of Mecca (1908-1917), King of the Hejaz, and King of the Arabs, Caliph of the Arab and Muslim world.