The declaration of war by Turkey on Great Britain furnished the Emir with the chance which he had long awaited, and the atrocities committed by the Turks in Syria at the beginning of the war caused the oppressed Arabs to turn to him as their national champion. He at once threw in his lot with the British, though not openly at first, and set to work, with the fierce energy characteristic of him, to stir up the tribes of the Hedjaz against the Turks.
The outbreak of the rebellion was precipitated by the arrival at Medina in May 1916 of a large Turkish force, charged with the task of re-establishing the waning authority of the Sultan in the Hedjaz. The Emir himself, though as full of energy and determination as ever, was now too old to bear the rigours of a desert campaign, and accordingly placed the command of his Bedouin followers in the hands of his three eldest sons Ali, Abdullah, and Feisal. Of Ali we know little, though he was active in the summer of 1918 and in the early part of 1917. Abdullah, the second son, was of a retiring disposition, a theologian and philosopher, and a deep student of the Koran. Feisal alone inherited his father's energy and power of command, without, however, the old man's ungovernable temper. The youngest son, Zeid, was still only a boy.
A line of Arab pickets was established round Medina, under the command of Feisal, and the railway north of the town was cut in several places. But the Arabs, not being provided at this time with explosives, and being ignorant of modern methods of demolition, did not effect enough before being driven off by relief parties with machine guns, to interrupt seriously the communication of Medina with the north, and the besieging force, short of arms and supplies, and without artillery, could do little more than watch the city from afar. Jiddah, however, the port of Mecca, which was attacked on June 9th, held out barely a week. Cut off from Mecca by the loss of the military block-houses on the road, and bombarded by British warships and aeroplanes, the Turkish garrison surrendered on the 16th June. The fall of Mecca followed a month later, and an Arab force under Sherif Abdullah then proceeded to blockade the hill town of Taif, where the bulk of the Turkish forces, outside Medina, was established in summer quarters. This place held out till near the end of September, when Ghalib Pasha, the G.O.C., despairing of help, and cut off by the Arabs from all sources of supply, surrendered with the garrison of 2000 men.
By the end of the year all the small Turkish posts scattered throughout the Hedjaz had fallen to the Arabs. Medina still held out, and it was clear that the Arab forces, indifferently armed, and inexperienced in modern siege warfare, could not hope to reduce this city. The Turkish garrison, with the lines of communication troops along the railway to the north, numbered some 15,000 men, well-armed and equipped, and in all respects capable of prolonged resistance.
Acting on the advice of the British officers with them, the Arabs, therefore, abandoned for the time being all attempts on Medina, and concentrated all their efforts on a systematic attack on the Hedjaz Railway north of the town. During the first six months of 1917 a constant succession of raids so interrupted the traffic on the railway that the Turks could with difficulty keep open their communications between Medina and Damascus.
In July 1917 the Emir Feisal seized Akaba, at the north end of the Red Sea, and made this place his base for further raiding operations on the railway as far north as Maan.
In January 1918 he succeeded in destroying the branch line to the Hish Forest, from which the Turkish locomotives were drawing their fuel, and then attacked Maan itself (see p. 153.) Though unable to capture the town, the Arabs established themselves across the railway two miles farther south, and, in the course of the succeeding three months, destroyed seventy miles of the line. Medina was thus finally isolated, and the garrison was faced with the two alternatives of holding out in the town till the end of the war, or of attempting to cut a way out to the north. As the latter alternative meant almost certain destruction, the Turks decided to stay where they were. They remained in Medina till they were compelled to surrender, under the terms of the Armistice of the 31st October 1918.
The strong position taken up by the Turkish IVth Army east of the Jordan during the summer of 1918, prevented the Emir from making any further move northwards. He remained about Maan, collecting his resources for the coming struggle, and carrying on a vigorous propaganda among the surrounding tribes, till the British advance in September caused the IVth Army to retire, and gave the Arabs the opportunity of completing the task to which they had set themselves in 1916.