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[citation needed] and revolted against the caliph[citation needed] 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. Hussain instead sided with the United Kingdom of Great Britain and Ireland in the thick of war. T. E. Lawrence was instrumental in this revolt. Hussain occupied Mecca and besieged Medina. It was one of the longest sieges in history that lasted till even after the end of war. Fahreddin Pasha was the defender of Medina. He was called "t