Medina, an Islamic holy city in Arabia, underwent a long siege during World War I. Medina was at the time part of the Ottoman Empire. In the war, the Ottoman Empire sided with the Central Powers. Sharif Hussain of Mecca betrayed and revolted against the caliph and the Ottoman Empire which, under the leadership of the secular and nationalistic Young Turks, had ignored the wishes of the Caliph and sided with the Central Powers.