The speed with which Lawrence moved and the unexpected direction of his attacks, along with his habit of “snipping” telegraph wires wherever he could, spread confusion at every level of the Turkish armies on both sides of the Jordan. The action convinced General Liman von Sanders, head of the German military mission to Turkey, and now de facto commander of the Turkish forces facing Allenby, whose headquarters was in Nazareth, that when Allenby’s attack came, it would be directed away from the coast and toward the east.

At 4:30 a.m. on September 19, 385 guns opened fire on the Turkish front line in Palestine for fifteen minutes. This firing was followed by a full-scale infantry assault advancing behind a “creeping” artillery barrage that drove the startled Turks from their trenches. So firmly had the Turks been convinced that the assault would be toward the Jordan River that they had thinned out their infantry on the coastal plain, and their defenses quickly crumbled. Ironically, one redoubt held out against the repeated attacks of the small French detachment (approximately of brigade strength), but by 7 a.m. Allenby’s forces had reached all their objectives. (Some divisions advanced “7,000 yards in 2% hours,” a rate of advance unthinkable on the western front.) By midday, the Turkish Eighth Army “had broken in hopeless confusion,” and its demoralized remnants were streaming northwest under constant bombing attack by British aircraft.

Once the infantry had punched a hole in the Turkish line, Allenby poured his cavalry in, en masse, in the Napoleonic manner. For many of the British and Australian troopers, it was the first opportunity to use their newly sharpened sabers in combat. So swift were the Turkish collapse and the British advance that the Thirteenth Brigade of the British Fifth Cavalry Division clattered into Nazareth at dawn on September 20, almost forty miles north of its starting point, forcing an astonished General von Sanders, whose lines of communication had been so deftly cut by Lawrence, and who therefore had no idea of the extent of his army’s disintegration, to flee from his headquarters—which was being defended by staff officers with carbines and by “clerks, orderlies, etc.” firing from the windows—to avoid capture. By the end of the day the advance scouts of Allenby’s cavalry were approaching the Jordan River, just south of the Sea of Galilee, while his infantry was wheeling away from the coast into the hills of Samaria, to take Nablus. Some idea of what conditions were like can be gleaned from the official military handbook for Palestine, which notes, “Nothing is known of the climate [of the Jordan Valley] in summer time, since no human being has yet been found to spend summer there.”

“Early on September 21st,” Liddell Hart wrote, “British aircraft sighted a large column [of Turks] winding down the steep gorge from Nablus towards the Jordan…. Four hours’ continuous bombing and machine-gunning by relays of aircraft reduced this procession to stagnation, and inanimate chaos of guns and transport.” Everywhere, the story was the same. The Turkish Seventh and Eighth armies, west of the Jordan, had for all intents and purposes ceased to exist except as isolated mobs of starving, unarmed men, desperate to surrender. The strongest Turkish force, the Fourth Army, east of the Jordan, was also rapidly losing cohesion. Lawrence had disabled the railroad, so the troops were forced to retreat on foot, without water, rations, or forage for the animals, and exposed to “constant pinpricks” by the Bedouin, who swept out of the desert to shoot and plunder the stragglers and the wounded. Haifa, with its vital port, was captured on September 23 by a bold cavalry advance around both sides of Mount Carmel, carried out by two Indian regiments of the Fifth (Imperial) Cavalry Division, the Mysore and the Jodhpur Lancers, with the addition of a squadron of the Sherwood Rangers, effectively placing every major city in Palestine in British hands.

At this point, the main danger to the Arab forces was from the air, since Allenby did not have enough aircraft to provide what would later come to be called “air cover” over the vast area of the Arab advance. The Arabs were still particularly sensitive to being bombed or machine-gunned from the air. This no doubt explains Lawrence’s hastily improvised raid on an advance Turkish landing field on his way back to Azrak;

during this raid, his armored car was bombed, sending a shower of broken stone through the vision slit, wounding his hand, blowing off a tire, and nearly overturning the vehicle in a ditch. He complained of “feeling like sardines in a doomed tin,” and remarked, “Of all dangers give me the solitary sort.” But although he had gone five nights without sleep, he pressed on to provide cover for another railway demolition, then carried out a nighttime “running fight” between his armored cars and a Turkish train, racing alongside the track in the darkness “lit up by the green shower of tracer bullets.”

On September 21 Lawrence reached Azrak, where an airplane landed early the next morning to bring him news of Allenby’s victory on the west bank of the Jordan. He immediately suggested that Feisal should set in motion “the long-delayed general revolt in Syria.” This was a significant decision. Both Feisal and Lawrence had discouraged any large-scale uprising in Syria, so long as there was any danger of the Turks’ gaining the upper hand, as they had done in March and April, when Allenby had been driven back from Amman and Salt. Any rising under those circumstances would simply lead to savage and widespread executions by the Turks. This time, however, it was clear that the Turks had been completely defeated, and that the only question was whether the remnants of the Turkish Fourth Army could reach Damascus before the British cavalry or the Arabs did. To Lawrence, what mattered now was to take advantage of the loophole in the Sykes-Picot agreement, the somewhat ambiguous language acknowledging that the Arabs might keep those territories they themselves captured during the course of the war. A careful parsing of the documents would also reveal that everything in them was subject to French claims, and the French had already claimed Lebanon and Syria (including Damascus). Still, Lawrence hoped that if the Arabs captured Damascus and a Syrian government was installed there before the British arrived, the world—and particularly the United States—might accept a fait accompli and might also accept the British government’s view, which was that the Sykes-Picot agreement was a “dead letter,” and superseded by events. He hoped, too, that the fall of the imperial Russian government,the unexpected strength of the Arab contribution to victory, and Woodrow Wilson’s demand for an end to secret treaties—and to European colonial acquisitions made without the consent of native populations—would prevail over the agreement. It was a slim reed on which to build a nation, as both Lawrence and Feisal recognized, particularly since urban Syrians were, as they still are, sharp and sophisticated traders, whereas rural Syrians were for the most part peasant farmers, few of them likely to greet with pleasure a government by King Hussein, or by his son Feisal.

In the morning, Lawrence flew directly to Ramleh, and drove from there to General Allenby’s headquarters in Palestine, where he “found the great man at work in his office unmoved” by the magnitude of his victory. Allenby personally briefed Lawrence on the next stage of his advance—the Australian Mounted Division (Major-General W. G. Hodgson) and the Fifth Cavalry Division (Major-General H. J. M. Mac Andrew) would turn north of the Sea of Galilee and advance on Damascus, while the Fourth Cavalry Division (Major-General Sir G. deS. Barrow) would strike east to capture Deraa, and then turn north toward Damascus. From one point of view, all this was welcome news to Lawrence—Allenby would shortly reach Damascus, very likely forcing the Turkish government to sue for peace. From another point of view, it meant that Lawrence’s hope of an independent Arab state in Syria depended on getting Feisal and the Arab forces into Damascus before Allenby’s cavalry divisions arrived—a very narrow window of opportunity. Allenby, always well informed, was aware of this, and in fact strictly warned Lawrence against attempting an “independent coup” in Damascus; the Arab forces, Allenby told him, should cooperate with the British Fourth Cavalry Division to cut off the retreat of the Turkish Fourth Army, and let the British and Australian forces deal with Damascus and move on. On the subject of air cover, Allenby was more generous; he agreed to provide the latest Bristol fighters to operate from the airstrip Lawrence had created in the desert at Umtaiye, about forty miles south of Deraa, and since there was no fuel there, to provide a giant Handley-Page bomber, the first to reach the Middle East, to shuttle back and forth loaded with cans of gas.