Attack by Chaytor's Force against the Ottoman Empire's Fourth Army
The Third Transjordan attack by Chaytor's Force, part of the British Empire's Egyptian Expeditionary Force (EEF), took place between 21 and 25 September 1918, against the Ottoman Empire's Fourth Army and other Yildirim Army Group units. These operations took place during the Battle of Nablus, part of the Battle of Megiddo which began on 19 September in the final months of the Sinai and Palestine campaign of World War I. Fought on the right flank and subsidiary to the Battle of Nablus, the Third Transjordan attack began northwards, with the assault on Kh Fasail. The following day a section of Chaytor's Force, attacked and captured the Ottoman Empire's 53rd Division (Seventh Army) on the main eastwards line of retreat out of the Judean Hills across the Jordan River. Retreating columns of the Yildirim Army Group were attacked during the battle for the Jisr ed Damieh bridge, and several fords to the south were also captured, closing this line of retreat. Leaving detachments to hold the captured bridge and fords, Chaytor's Force began their eastwards advance by attacking and capturing the Fourth Army garrison at Shunet Nimrin on their way to capture Es Salt for a third time. With the Fourth Army's VIII Corps in retreat, Chaytor's Force continued their advance to attack and capture Amman on 25 September during the Second Battle of Amman. Several days later, to the south of Amman, the Fourth Army's II Corps which had garrisoned the southern Hejaz Railway, surrendered to Chaytor's Force at Ziza, effectively ending military operations in the area.
The British Empire victories during the Third Transjordan attack resulted in the occupation of many miles of Ottoman territory and the capture of the equivalent of one Ottoman corps. Meanwhile, the remnants of the Fourth Army were forced to retreat in disarray north to Damascus, along with the remnants of the Seventh and Eighth Armies after the EEF victories during the Battle of Sharon and Battle of Nablus. Fighting extended from the Mediterranean Sea during these seven days of battle, resulting in the capture of many thousands of prisoners, and extensive territory. After several days pursuing remnant columns, Desert Mounted Corps captured Damascus on 1 October. The surviving remnants of Yildirim Army Group which escaped Damascus were pursued north during the Pursuit to Haritan when Homs was occupied and Aleppo was captured by Prince Feisal's Sherifial Army Force. Soon after, on 30 October, the Armistice of Mudros was signed between the Allies and the Ottoman Empire, ending the Sinai and Palestine campaign.
Background.
Following the victory at the Battle of Jerusalem at the end of 1917, and the Capture of Jericho in February 1918, the Egyptian Expeditionary Force (EEF) crossed the Jordan River, establishing bridgeheads in March prior to the First Transjordan attack on Amman. These bridgeheads remained after the Second Transjordan attacks on Shunet Nimrin and Es Salt when a second withdrawal back to the Jordan Valley took place from 3 to 5 May. This marked the end of major operations in the area until September 1918. General Edmund Allenby, the commander of the EEF, decided to occupy the Jordan Valley during the summer of 1918 for a number of reasons. A retreat out of the valley would further enhance the morale of the German and Ottoman forces, and their standing among the peoples living in the region, following their two Transjordan victories. So important did Allenby consider the support of the Hedjaz Arabs to the defence of his right flank, that they were substantially subsidised:
 ;templatestyles src="Template:Blockquote/styles.css" / ;I think we shall manage the subsidy required as well as the extra £50,000 you require for Northern Operations ... I am urging for another £500,000 additional to the £400,000 en route from Australia and I am sure you will do what you can, through the WO to represent the importance of not risking a delay again in the payment of our Arab subsidy.
The road from the Hedjaz railway station at Amman to Shunet Nimrin remained a serious threat to the occupation of the Jordan Valley, as a large German and Ottoman force could quickly be moved along this line of communication from Amman to Shunet Nimrin, from where they could mount a major attack into the Jordan Valley. As Allenby explains,
 ;templatestyles src="Template:Blockquote/styles.css" / ;I am not strong enough to make holding attacks on both flanks, and the Turks can transfer their reserves from flank to flank as required. The Turks have more of these, the VII Army have 2400, and the VIII Army 5800 in Reserve. I must maintain my hold on the bridges of the Jordan, and my control of the Dead Sea. This will cause the Turks to keep a considerable force watching me, and ease pressure on Feisal and his forces. It is absolutely essential to me that he should continue to be active. He is a sensible, well–informed man; and he is fully alive to the limitations imposed on me. I keep in close touch with him, through Lawrence. I have now in the valley two Mounted Divisions and an Indian Infantry Brigade. I cannot lessen this number yet.
By July, Allenby was "very anxious to make a move in September," when he aimed to capture Tulkarm, Nablus and the Jisr ed Damieh bridge across the Jordan River. He stated, "The possession by the Turks of the road Nablus–Jisr ed Damie–Es Salt is of great advantage to them; and, until I get it, I can't occupy Es Salt with my troops or the Arabs." He hoped the capture of this important Ottoman line of communication from Nablus along the Wadi Fara to the Jordan River at Jisr ed Damieh and on to Es Salt would also "encourage both my own new Indian troops and my Arab Allies."
EEF front line.
From the departure of the Australian Mounted Division in August steps were taken to make it appear the valley was still fully garrisoned. On 11 September the 10th Cavalry Brigade, which included the Scinde Horse, left the Jordan Valley. They marched via Jericho, to Talaat de Dumm, then a further to Enab, reaching Ramleh on 17 September in preparation for the beginning of the Battle of Megiddo.
Chaytor's Force held the right flank from their junction with the XX Corps in the Judean Hills north west of Jericho, across the Jordan Valley, and then southwards through the Ghoraniye and Auja bridgeheads to the Dead Sea. This area was overlooked by well sited Ottoman or German long range guns and an observation post on El Haud.
Ottoman front line.
The Ottoman front line had been strengthened after the Second Transjordan attack. It began in the south, where Ottoman cavalry guarded tracks to Madaba before continuing with strongly wired entrenchments. In front of these, advanced posts extended from the foothills opposite the ford across the Jordan River at Makhadet Hijla to about north of the Jericho to Es Salt road. The road had been cut at the Ghorianyeh Bridge before the First Transjordan attack, in the vicinity of Shunet Nimrin. The front line was strengthened by advanced posts which were also wired on the left flank at Qabr Said, Kh. el Kufrein and Qabr Mujahid. From their right flank in the foothills a wired line of redoubts and trenches facing south ran from north of Shunet Nimrin, across the Jordan Valley to the Jordan River, south of the Umm esh Shert ford. This line was continued west of the river by a series of individual "wired-in redoubts with good fields of fire," then as a series of trenches and redoubts along the northern or left bank of the Wadi Mellaha. These were followed by a "series of trenches and redoubts towards Bakr Ridge which were entrenched but not wired. A strong advanced position of well built sangars and [sic] [which were] wired in was held at Baghalat." Bakr Ridge in the Judean Hills was situated to the west of the salient at El Musallabe which was held by the EEF. The Ottoman front line was supported by entrenched positions on Red Hill beside the Jordan River, which was also the site of their main artillery observation point.
Battle of Megiddo 19 to 20 September.
During the first 36 hours of the Battle of Megiddo, between 04:30 on 19 September and 17:00 on 20 September, the German and Ottoman front line had been cut by infantry of the EEF's XXI Corps. This allowed the cavalry of the Desert Mounted Corps to pass through the gap and begin their ride towards their objectives at Afulah, Nazareth, and Beisan. The two Ottoman armies were left without effective communications, and so could not organize any combined action against the continuing onslaught by the British Empire infantry in the Judean Hills. The Ottoman Seventh and Eighth Armies were forced to withdraw northwards along the main roads and railways from Tulkarm and Nablus, which converged to run through the Dothan Pass to Jenin on the Esdrealon Plain. There, retreating columns from these two Ottoman armies would be captured during the evening of 20 September by the 3rd Light Horse Brigade, who already occupied the town.
Liman von Sanders escapes.
Otto Liman von Sanders, the commander of the Yildirim Army Group, was forced out of his headquarters at Nazareth during the Battle of Nazareth on the morning of 20 September by elements of the 5th Cavalry Division. He drove via Tiberias and Samakh where he alerted the garrisons, to arrive at Deraa on the morning of 21 September, on his way to Damascus. At Deraa, Liman von Sanders received a report from the Fourth Army, which he ordered to withdraw to the Deraa to Irbid line without waiting for the troops which garrisoned the southern Hejaz.
Prelude.
Chaytor's Force.
While the Battles of Sharon and Nablus were taking place, it was necessary to deploy a strong force, to defend the right flank of the Desert Mounted Corps, the XXI and the XX Corps fighting from the Mediterranean coast and into the Judean Hills. Their right flank in Jordan Valley was protected by Chaytor's Force from the threat of a flanking attack by the Ottoman Fourth Army. This composite force commanded by Major General Edward Chaytor has been described by Bou as "nearly equivalent to two divisions," being a reinforced mounted infantry division of 11,000 men. By the end of operations on 30 September Chaytor's Force consisted of "8,000 British, 3,000 Indian, 500 Egyptian Camel Transport Corps troops."
Medical support.
In addition to the Anzac Mounted Division's medical units, the 1/1st Welsh and the 157th Indian Field Ambulances, the Anzac Field Laboratory, and a new operating unit formed from personnel of the 14th Australian General and the 2nd Stationary Hospitals, were attached to Chaytor's Force.
A receiving station was formed from the immobile sections of light horse and mounted rifle brigades' field ambulances, a section from the 1/1st Welsh and the 157th Indian Field Ambulances with an operating unit, the Anzac Field Laboratory, and a detachment from an Egyptian hospital. This Receiving Station took over the site near Jericho, occupied by the main dressing station during the two Transjordan attacks, which could accommodate 200 patients in mud huts, 400 patients in tents, and 700 patients in the abandoned Desert Mounted Corps headquarters.
Air support.
The Royal Air Force's (RAF)'s 5th (Corps) Wing, headquartered at Ramle, deployed one flight of the No. 142 Squadron RAF on 18 September to Chaytor's Force. The flight was based at Jerusalem, with responsibility for cooperation with artillery, contact patrols, and tactical reconnaissance up to in advance of Chaytor's Force.
No. 1 Squadron, Australian Flying Corps (AFC), operating Bristol Fighters, was to carry out bombing and strategic reconnaissance missions, provide a general oversight of the whole Megiddo battlefield, and report all developments. Meanwhile, Nos. 111 and 145 Squadrons, which were equipped with S.E.5.a aircraft, were to constantly patrol over Jenin aerodrome throughout the day to bomb and machine gun all targets in the area, and prevent any aircraft from taking off. Airco DH.9 aircraft from No. 144 Squadron were to bomb the Afulah telephone exchange and railway station, the Messudieh Junction railway lines, and the Ottoman Seventh Army headquarters and telephone exchange at Nablus. The newly arrived Handley Page bomber, armed with 16 bombs and piloted by the Australian Ross Smith, was to support No. 144 Squadron's bombing of Afulah.
Jordan Valley deployments.
Chaytor took command of