User:Mohammad adil/sandbox35435

The Battle of Yarmouk (معركة اليرموك, also spelled Yarmuk, Yarmuq or Hieromyax) comprised a series of engagements between the Rashidun Caliphate and the Byzantine Empire over six days in August 636, near the Yarmouk River, along what is today the border between Syria and Jordan, south-east of the Sea of Galilee, and resulted in a decisive Muslim victory which permanently ended Byzantine rule south of Anatolia. It is regarded as one of the most decisive battles in military history. The battle marked the first great wave of Islamic conquests after the death of Muhammad, heralding the rapid advance of Islam into the then Christian Levant.

Emperor Heraclius, in order to check the Muslim advance and to recover lost territory, sent a massive expedition to the Levant in May 636. As the Byzantine army approached, Muslims abandoned Syria and retreated all their forces to the Yarmouk plains close to Arabia where, after being reinforced they decisively defeated the Byzantine troops. The battle is also considered to be one of Khalid ibn al-Walid's most decisive victories, and cemented his reputation as a great tactician and cavalry commander.

Prelude
The Islamic Prophet Muhammad ibn ‘Abdullāh died in June 632, and Abu Bakr was appointed Caliph and his political successor. Troubles emerged soon after Abu Bakr's succession. Several Arabic tribes revolted against Abu Bakr. This was the start of the Ridda wars (Arabic for the Wars of Apostasy). Abu Bakr declared war against the rebels, The Campaign of the Apostasy was fought and completed during 632, and by 633 Arabia was united under the central authority of the Caliph at Medina. Once the rebellions had been put down, Abu Bakr began a war of conquest, beginning with Iraq, the richest province of the Persian Empire. He sent his most brilliant general, Khalid ibn al-Walid, to invade the Sassanid Persian Empire. After successful campaigns against the Sassanid Persians and the conquest of Iraq, Abu Bakr's confidence grew, and once Khalid established his stronghold in Iraq, Abu Bakr issued a call to arms for the invasion of Syria in February 634. The Muslim invasion of Syria was a carefully planned, coordinated and organised series of military operations using strategy well able to deal with Byzantine defensive measures. Abu Bakr organised the army into four corps, each with its own commander and objective. This tactic of penetrating by several self-sufficient armies eliminated the traditional distinction between "front" and "rear". These armies soon proved to be small, and called for reinforcement when Byzantine emperor Heraclius, disturbed by this Arabian movement, sent in a foray, his brother Theodore to lead an army of Syrian garrisons against the invaders. Khalid was sent by Abu Bakr from Iraq to Syria with reinforcements and to lead the invasion. The battle thus fought was at Ajnadayn, where the Byzantines were decisively defeated. Damascus fell in September 634, followed by the Battle of Fahl where the last strong garrison of Palestine was defeated and routed. Caliph Abu Bakr died in 634, making Umar his successor. While Abu Bakr had been successful in invading Syria, Umar was determined to extend the reach of his kingdom and continued the conquest deeper into Syria. Though previous campaigns led by Khalid ibn al-Walid were successful, he was replaced by Abu Ubaidah ibn al-Jarrah. The Arabs having secured southern Palestine now advanced up the trade route that went east of Jordan and over to Damascus and the Orontes valley. Tiberias and Baalbek fell to the Arabs without much struggle and the Muslims Conquered Emesa later that year. From thereon, the Muslims continued their conquest across the Levant.

Byzantine counter-attack
By 635, Muslims had conquered most of Palestine and southern Syria and with Emesa under their power, the Muslims were just a march away from Aleppo, a Byzantine stronghold and Antioch where Emperor Heraclius resided. Now seriously alarmed by the losses, the Byzantine Emperor Heraclius started preparations for a counter-attack to roll back the lost region. In 635 Yazdgerd III, the emperor of Persia, sought alliance with Heraclius. Heraclius married off his daughter (according to traditions, his grand daughter) Manyanh to Yazdegerd III, an old Roman tradition to show alliance. While Heraclius prepared for a major offense in Levant, meanwhile Yazdegerd was supposed to mount a counter-attack in Iraq. This was supposed to be a well-coordinated attack by both emperors, Heraclius in the Levant and Yazdegerd in Iraq, to annihilate their common enemy Caliph Umar. However, Umar, likely having intelligence of this alliance, engaged Yazdegerd III in peace negotiations, apparently inviting him to Islam. While Heraclius launched his offense in May 636, Yazdegerd, probably owing to exhausted conditions of his government, could not coordinate with Heraclius' offense, and a would be decisive plan missed the mark. While Umar won a decisive victory against Heraclius at Yarmouk, Yazdegerd III, was being engaged and trapped in deception tactics by him. Yazdegerd III lost his imperial army at the Battle of Qadisiyyah in November 636 three months after Yarmouk, ending Sassanid control west of Persia. Emperor Heraclius assembled a large army in northern Syria and Antioch in late-635 to halt the Arab invasion. Preparations started in late 635, and by May 636, a large force was put under arms and was concentrated at Antioch in northern Syria. The assembled army consisted of contingents of Byzantines, Slavs, Franks, Georgians, Armenians and Christian Arabs. This force was organized into five armies, the joint leader of which was Theodore Trithourios the Sakellarios, and Vahan, the king of Armenia – who commanded a purely Armenian army, was the field commander, Buccinator (Qanateer), a Slavic prince commanded the Slavs and Jabalah ibn al-Aiham, king of the Ghassanid Arabs, commanded an exclusively Christian Arab force. The remaining contingents, all European, were placed under Gregory and Dairjan. . Heraclius himself supervised the operation from Antioch. Byzantine sources mention Niketas son of Shahrbaraz among the commanders but it is not certain which army he commanded. At that time, the Rashidun army was split in four groups: one under Amr ibn al-Aas in Palestine, one under Shurahbil in Jordan, one under Yazid ibn Abu Sufyan at Damascus-Caesarea region and the last one under Abu Ubaidah ibn al-Jarrah along with Khalid ibn al-Walid at Emesa. Being geographically divided up in each direction, Heraclius sought to exploit this situation and planned to attack and destroy each of these Muslim corps separately by putting a large concentration of troops against each of them in turn. Thus, reinforcements were sent to Caesarea under Heraclius' son Constantine, probably to tie down Yazid's forces there, which were besieging Caesarea, so that it would not move to join other Muslim corps to help them. The imperial army moved out from Antioch and northern Syria sometime in the middle of June 636. The imperial was to operate under the following plan:
 * Jabla's lightly armed Christian Arabs would march to Emesa from Allepo via Hama and hold the main Muslim army at Emesa.
 * Dairjan would make a flanking movement moving between the coast and Allepo road and approach Emesa from west striking at Muslim's left flank while they were being held frontally by Jabla.
 * Gregory would strike the Muslim's right flank, approaching Emesa from the north-east via Mesopotamia.




 * Qanateer would march along the coastal route occupy Beirut from where he was to attack weakly defended Damascus from the west to cut off the main Muslim army at Emesa.
 * Vahan's corps would act as a reserve and would approach Emesa via Hama.

The Muslim strategy
Muslims came to know about Heraclius's preparations at Shaizar, through Roman prisoners. Alert to the possibility of being caught with separated forces that could be destroyed in detail, as Heraclius indeed planned, Khalid, in a council of war, advised Abu Ubaidah to pull back from northern and central Syria, as well as from Palestine and concentrate the entire Rashidun army in one place. Abu Ubaidah ordered the concentration of troops in the vast plain near Jabiya, as this was suitable for cavalry charges, and from there it would be easier for the caliph to send reinforcements and thus a strong, united force could be fielded against the Byzantine armies. The position also benefited from close proximity to the Rashidun stronghold of Najd, in case of retreat. Ibn al-Jarrah, commander in chief of the Muslim Arab armies, thus ordered the commanders to surrender the territory under their control and withdraw the army to Jabiya. In addition, he ordered the commanders to return the jizya (tribute) to the people who had paid it. At first the Muslim forces concentrated at Jabiya, but there they were subject to raids from pro-Byzantine Ghassanid forces; the region was also not suitable to camp as there was a strong Byzantine garrison in Caeseara that could attack the Muslim rear while they were held in front by the Byzantine army. On Khalid’s advice they retreated to Dara’ah and dayr Ayyub, covering the gap between Yarmouk Gorges and Harra lava plains, and established a line of camps in the eastern part of the plain of Yarmuk. This was a strong defensive position and this maneuver of the Muslims forced Byzantine troops to engage in a decisive battle, which they usually avoided. During all this, there were no major conflicts except for a minor skirmish between Khalid's elite light cavalry Mobile guard and the Byzantine advance guard.

Battlefield
The battlefield lies about 65-kilometres south-west of the Golan heights, an upland region currently on the frontier between Israel, Jordan and Syria, east of the Sea of Galilee. The battle was fought on the plain of Yarmouk which was enclosed on its western and southern edges by a deep ravine, known as Wadi-ur-Raqqad with banks about 30 m deep. This ravine joins the Yarmouk River, a tributary of the Jordan River on its south. The stream had very steep banks from 10–30 m deep. On the north lay the Jabiya road and to the east lie the Azra hills, although these hills were outside the actual field of battle. Strategically there was only one prominence in the battlefield – a 100 m high elevation known as the hill of Jamu'a (meaning gathering). For the Muslim troops concentrated on it, it gave a good view of the plain of Yarmouk. Ravine on the west of the battlefield was accessible at a few places in 636 AD, and had one main crossing, a bridge over the ravine, near the present day village of Kafir-ul-Ma. The Yarmouk plain was quite suitable for both the armies, it had the ample supply of water and pastures to feed the mounts of both the troops. The plain was excellent for cavalry maneuvers.

Troop deployment
Most early Muslim accounts state the size of the Muslim forces as between 24,000 and 40,000 and the number of Byzantine forces at between 100,000 and 200,000. Modern estimates of the sizes of the respective armies vary: Estimates for the Byzantine army are mostly between 80,000 and 120,000, with some estimates as low as 50,000 and 15,000-20,000. Estimates for the Rashidun army are between 25,000 and 40,000. These figures come from studying the logistical capabilities of the combatants, the sustainability of their respective bases of operations, and the overall manpower constraints affecting the Romans and Arabs. Most scholars, however, agree that the Byzantine army and their allies outnumbered the Muslim Arabs by a sizeable margin

Rashidun
The army was lined up on a front of 11 miles, with its left on the Yarmouk River a mile before the ravine began and its right on the Jabiya road, with substantial gaps between the divisions so that they could cover the whole area that Byzantines were covering with their 12 mile long battle front. The center of the army was under the command of Abu Ubaidah ibn al-Jarrah (left half) and Shurhabil bin Hassana (right half). The left wing was under the command of Yazid and the right wing was under Amr ibn al-A'as. Center, left and right wings were given cavalry regiments under command, to be used as a reserve for counter attack in case they were pushed back by the Byzantines. Behind the center stood mobile guard under the personal command of Khalid. When Khalid was occupied in the conduct of the battle, Zirrar ibn al-Azwar would command the mobile guard. The army pushed out a line of scouts to keep the Byzantines under observation. The battle formation of Tabi'a was used which was a type of close defensive formation. During a council of war, Khalid ibn Walid, the former commander in chief of the Rashidun army in the campaign of Syria, offered his services as a commander of the Muslim army until the battle was over and it was given to him that day; Abu Ubaidah ibn al-Jarrah's military credentials were not as high as Khalid's. After taking command, Khalid reorganized the army into infantry and cavalry regiments, with cavalry making up a quarter of the army. Khalid further divided the army into 36 infantry regiments and four cavalry regiments; with his cavalry elite, mobile guard, held in reserve. Over the course of the battle Khalid would repeatedly make critical, decisive use of this mounted reserve. In late July 636, Mahan sent Jabla with his lightly armored Christian Arab forces to check the strength of the Muslim front, but they were repulsed by the mobile guard under Khalid. After this initial operation, no military activities occurred for a month.

Weaponry
Helmets included gilded helmets similar to the silver helmets of Sassanid empire. Mail was commonly used to protect the face, neck and cheek either as an aventail from the helmet or as a mail coif. Heavy leather sandals as well as Roman type sandal boots were also typical of the early Muslim soldiers. Armor included hardened leather scale or lamellar armour and mail armor. Infantry soldiers were more heavily armored than horsemen. Hauberks and large wooden or wickerwork shields were used. Long-shafted spears were used, infantry spears were two and a half meter long while cavalry spears were up to five and a half meters long. Short infantry swords like the Roman gladius and Sassanid long swords were being used. Swords were hanged in baldric. Bows were about two meters long when unbraced, similar in size to the famous English longbow. The maximum useful range of the traditional Arabian bow was about 150 meters. Early Muslim archers were infantry archers who proved to be very effective against cavalry.

Byzantine
A few days after the Muslims, Byzantine army preceded by the lightly-armed Ghassanids of Jabla, moved forward and established their strongly fortified camps just north of the Wadi-ur-Riqqad, Vahan deployed the Imperial Army forward of Allan, with a front about 13 kilometres long, as he was trying to cover the whole area between the Yarmouk gorge and the Roman road to Egypt, and there had been substantial gaps between the Byzantine divisions. He used his four regular armies to form the line of battle, extending from the Wadi Allan to the south of the Hill of Jabiya. The right wing was commanded by Gregory and the left by Qanateer. The centre was formed by the army of Dairjan and the Armenian army of Mahan—both under the command of Dairjan. The Roman regular heavy cavalry, the cataphract was distributed equally among the four armies, with each army deployed with its infantry holding the front and its cavalry held as a reserve in the rear. Ahead of the front line, across the entire 11-mile front, Vahan deployed the Christian Arab army of Jabla, which was all mounted on horses and camels. This army acted as a screen and skirmish line, until it would be joined by the main army. The army of Gregory, which formed the right wing, used chains to link its footsoldiers together. All these footsoldiers had taken the oath of death. These chains were in 10-man lengths and were used as a proof of unshakeable courage on the part of the men, who thus displayed their willingness to die where they stood and not retreat. The chains also acted as an insurance against a breakthrough by enemy cavalry. However, modern historians suggest that Byzantines adopted the Graeco-Roman military formation known as the testudo formation in which soldiers would stand shoulder-to-shoulder with shields held high and a 10-to-20-man arrangement would be completely shielded on all sides, each soldier providing cover for an adjoining companion.

Weaponry
Byzantine cavalry were armed with the long sword known or spathion. They would also have a light wooden lance known as kontarion and a bow (toxarion) with forty arrows in a quiver, hung from a saddle or from the belt. Heavy infantry, known as skoutatoi, had a short sword and a short spear. Lightly-armed Byzantine troops, the archers, carried a small shield, a bow across the back—hung from the shoulder rather than a belt—and a quiver of arrows. Cavalry armour consisted of a mail hauberk with a mail coif and a helmet with a pendant, i.e., a throat-guard lined with fabric and having a fringe and cheek piece. Infantry were similarly equipped with a mail hauberk, helmet and leg armour. Light lamellar and scale armour was also used.

Tensions in Byzantine army
Rashisdun's strategy of withdrawing from the occupied areas and concentrating all of his troops for a decisive battle forced the Byzantines to concentrate their five armies in response. The Byzantines had for centuries avoided engaging in decisive battles, and the concentration of their forces created logistical demands for which the empire was ill-prepared. Damascus was the closest logistical base, but Mansur, leader of Damascus, couldn’t fully supply the massive Byzantine army that was gathered at the Yarmouk plain. Several clashes were reported with local citizens over supply requisition, as it was end of summer and there was a decline of pasturage. Greek court sources accused Vahan of treason for his disobedience to Heraclius’ command not to engage in large-scale battle with Arabs; given the massing of the Muslim armies at Yarmouk, however, Vahan had little choice but to respond in kind. Relations between the various Byzantine commanders were also fraught with tension. There was a struggle for power between Trithurios and Vahan, Jarajis and Qanatir (Buccinator). Jabla, the Christian Arab leader, was largely ignored, to the detriment of the Byzantines given his knowledge of the local terrain. Thus a mistrust was created between Greeks, Armenians, and Arabs. Longstanding ecclesiastical feuds between the Monophysite and Chalcedonian factions, while of negligible direct impact, certainly increased underlying tensions. The effect of these feuds was decreased coordination and planning, one of the reasons for the catastrophic Byzantine defeat.

The battle
Vahan was instructed by Heraculis not to give battle until all avenues of peaceful negotiation had been explored. This was most probably done because Heraclius ally Yazdegerd III's forces were still not completely ready for offensive in Iraq. Accordingly, Vahan sent Gregory and then Jabla to negotiate, however their peace efforts failed. Before the battle, on Vahan’s invitation, Khalid came to talks but still with no result. This only delayed the battle for a month. On the other hand, Caliph Umar whose armies at Qadisiyyah were already facing a Sassanid army, in order to avoid a risk of decisive battle at a time with two great power devised his own genius plan. He ordered Saad to enter into negotiations with Persians and send emissaries to Yasdegerd III and his Rostam Farrokhzād apparently inviting them to Islam. This was most probably the delaying tactics employed by Umar on Persian front. Meanwhile he sent a reinforcement of 6,000 troops, mostly from Yemen as including 1,000 Sahaba (companions of Muhammad), among them a 100 veterans of the Battle of Badr, the first battle in Islamic History. The army also included citizens of the highest rank, such as Zubair ibn al-Awwam, Abu Sufyan, and his wife Hind bint Utbah. Umar apparently wanted to deal first with the Byzantines, as he had employed the best Muslim troops against them. Umar succeeded in his plan as a continuing stream of Muslim reinforcements, worried the Byzantines, who fearing that Muslims with such reinforcements will grow powerful, were left with no choice but to attack. Most probably the reinforcement that reached Muslims at Yarmouk was sent in various small bands, so as to give the impression of a continuous stream of reinforcement, in order to demoralize the Byzantines. The same fashion was exercised by Muslims reinforcement of Yarmouk's veterans who reached Qadisiyyah during the Battle of Qadisiyyah.

Day 1
The battle started on 15 August 636 At dawn both armies lined up for battle and were a little less than a mile apart. It is recorded in Muslim chronicles that before the battle would commence, George, a Byzantine commander of a unit in Byzantine right center, rode up to the Muslim line and converted to Islam; he would die the same day fighting on the Muslim side. The battle began with duels between the champions, Muslims mubarizuns came forwards for duels. These were specially trained swordsmen and lancers, with the objective to slay as many enemy commanders as possible to damage their morale. At midday, after losing a number of commanders to the Mubarizuns, Vahan attempted a limited offensive through the Byzantine infantry to test the strength and strategy of the Muslim army, and if possible, achieve a breakthrough wherever the Muslim front was weak. Only a third of the infantry advanced into battle on the orders of Vahan to test the defences of the Muslims, however the Byzantine assault was not a determined one. Many of the soldiers of the Imperial army were not accustomed to battle and were unable to press the attack as the Muslim veterans did. On some parts of the front the fighting was intense, but on the whole the action of this day could be described as steady and moderately hard. Vahan did not reinforce his forward infantry, and at sunset the action ended with the two armies separating and returning to their respective camps.

Day 2
On 16 August 636, Vahan in a council of war decided to launch his attack just before dawn, to catch the Muslim force unprepared as they conducted their morning prayers. He planned to engage the two of his central armies with the Muslim centre in an effort to stall them while the main thrusts would be against the wings of the Muslim army, which would then either be driven away from the battlefield or pushed towards the centre. To observe the battlefield, Vahan had a large pavilion built behind his right wing with an Armenian bodyguard force. He ordered the army to prepare for the surprise attack. Unbeknown-st to the Byzantines, Khalid had placed a strong outpost line in front during the night to counter surprises, which gave the Muslims time to prepare for battle. At the center, the Byzantines did not press hard, as this was meant to be a limited attack to pin the Muslim central corps in their position. Thus the center remained stable. But on the wings situation was different. Qanateer commanding the Byzantine left flank had a force of mainly Slavs, attacked and forced the Muslim infantry of right flank to retreat. Amr, the Muslim right wing commander ordered his cavalry regiment to counter attack, which checked the Byzantine advance and stabilized the battle line on the right for some time, but eventually retreated towards the base camp.

Khalid, aware of the situation at the wings, instructed the cavalry of right wing to attack at the northern flank of Byzantine left wing while with his mobile guard he attacked the southern flank of Byzantine left wing, while Muslim right wing infantry attacked from front. The three prong-attack forced Byzantine left wing to retreat to their original position and Amr regained his lost ground and started reorganizing his corps for another round. The situation on the Muslim left wing where Yazid commanded was slightly serious. Whilst the Muslim right wing enjoyed assistance from the mobile guard, the troops on the left wing were retreating back to their camps. Here the Byzantines had broken through the corps. The testudo formation that Gregory's army had adopted moved slowly but also had a good defence. Yazid used his cavalry regiment to counter attack but was repulsed. After a period of stiff resistance the warriors of Yazid finally fell back to their camps and for a moment Vahan's plan appeared to be succeeding. The centre of the Muslim army was pinned down and its flanks had been pushed back. However, neither flank had broken, though their morale was severely damaged. The retreating Muslim army were met by the ferocious Arab women at the camps. Led by Hind, the Muslim women dismantled their tents and armed with tent poles and charged at their husbands and fellow men singing an improvised song from the Battle of Uhud that then had been directed against the Muslims.

''O you who run from a constant woman

Who has both beauty and virtue;

And leave her to the infidel,

The hated and evil infidel,

To possess, disgrace and ruin.'' This boiled the blood of the retreating Muslims further and they fled back into the battlefield.

With the position on the right stabilised, the mobile guard cavalry moved towards the left wing. Khalid detached one regiment under Zirrar ibn al-Azwar and ordered him to attack the front of the army of Deirjan(left half of the center) in order to create a diversion and threaten the withdrawal of the Byzantine right wing from its advanced position. With the rest of the cavalry reserve he attacked Gregory's flank. Here again, under simultaneous attacks from the front and flanks, the Byzantines fell back, but more slowly because assuming their formation the men could not move as fast. At sunset the central armies broke contact and withdrew to their original positions and both fronts were restored along the lines occupied in the morning. The death of Dairjan and the failure of Vahan's battle plan left the Imperial army relatively demoralized, whereas Khalid's successful counter-attacks emboldened his troops.

Day 3
On 17 August 636, Vahan pondered over his failures and mistakes of the previous day. What bothered him the most was the loss of one of his commanders. The imperial Byzantine army decided on a less ambitious plan, aiming to break the Muslim army at a specific points. Vahan suggested to press upon the relatively exposed right flank. And it was decided to charge at the junction between the Muslim right half of centre and its right wing by Qanateer's Slavs to break the two apart and be fought with individually. The battle resumed with the Byzantine attacks on Muslims right flank and right half of the center. After holding the initial attacks by the Byzantines, the Muslim right fell back followed by right half of the center. They were again met by their own womenfolk who abused and ashamed them, the corps were able to reorganize some distance from the camp for a counter-attack. Knowing that the Byzantine army was focusing on the Muslim right, Khalid launched an attack with his mobile guard, along with the Muslim right flank cavalry. Khalid stuck at the right flank of Byzantines left half of the center, and the cavalry reserve of Muslims right half of the center stuck at the Byzantines left half of the center at its left flank. The Muslims right wing cavalry stuck at the left flank of Byzantines left wing. The combat soon accelerated into a bloodbath. Many fell on both sides and by dusk the Byzantines had been pushed back to their former positions and the situation restored to that existing at the beginning of the battle.

Day 4
18 August 636, the fourth day was to prove decisive. Vahan decided to persist with the previous day's war plan as he had been successful in inflicting damage on the Muslim right. Qanateer led two armies of Slavs against the Muslim right and right half of centre with a little assistance from the Armenianas and Christian Arabs led by Jabala. The Muslim right wing and right half of the center again fell back. Khalid entered the fray yet again with this mobile guard. He feared a general attack on a broad front which would make it impossible for him to repulse and as a precaution ordered Abu Ubaida and Yazid on the left centre and the left wings respectively to attack the Byzantine armies at the respective fronts. The attack would result in stalling the Byzantine front and preempt a general advance of the Imperial army. Khalid divided his mobile guard into two divisions and attacked both the flanks of Byzantine left half of the center, while infantry of Muslim right half of the center attacked from front. Under this three prong flanking manoeuvre, Byzantines fell back. Meanwhile Muslim right wing renewed it offense with its infantry from front and cavalry reserve attacking northern flank of Byzantine left wing. As the Byzantine left half of the center retreated under three prong attacks of Khalid, Byzantine left wing, having being exposed at southern flank, also fell back.

While Khalid and his mobile guard were dealing with the Armenian front throughout the afternoon, the situation on the other end was worsening. Byzantine horse-archers had taken to the field and subjected Abu Ubaidah and Yazid's troops to intense archery preventing them from penetrating their Byzantine lines. Many Muslim soldiers lost their sight to Byzantine arrows on that day, which thereafter became known as the "Day of Lost Eyes". The veteran Abu Sufyan also lost an eye. The Muslim armies fell back except for one regiment led by Ikramah bin Abu Jahal, which was on the left of Abu Ubaidah's corps. Ikramah covered the retreat of Muslims with his four hundred cavalry by attacking the Byzantine front, while the other armies reorganized themselves to counter-attack and gain their lost positions. All of Ikramah's men were either seriously injured or died that day. Ikrimah, a childhood friend of Khalid's were mortally wounded and died later in the evening.

Day 5
Early on 19 August 636, the fifth day of battle Vahan sent an emissary to the Muslim camp for a truce for the next few days so that fresh negotiations could be held, but the offer was rejected. Khalid knew that the Byzantines were no longer eager for battle. Up until now the Muslim army had adopted a largely defensive strategy, but Khalid now decided to take the offensive and reorganized his troops accordingly. All the cavalry regiments were grouped together into one powerful mounted force with the mobile guard acting as its core. The total strength of this cavalry group was now about 8,000 mounted warriors, an effective mounted corps for an offensive attack the next day. The rest of the day passed uneventful.

Day 6
On 20 August 636, the final day of battle, Khalid put into action a simple but bold plan of attack. With his massed cavalry force he intended to drive the Byzantine cavalry entirely off the battlefield so that the infantry, which formed the bulk of the imperial army, would be left without cavalry support and thus be exposed when attacked from the flanks and rear. At the same time he planned to push a determined attack to turn the left flank of the Byzantine army and drive them toward the ravine to the west. Khalid ordered a general attack on the Byzantine front and galloped his cavalry around the left wing of Byzantine, apart of cavalry engaged Byzantine left wing cavalry while rest of it attack at the rear of Byzantine left wing meanwhile Muslim right wing pressed against it from the front. Unser this two prong attack, Byzantine left wing fell back and collapse at Byzantine left half of the center, greatly disordering it. The remaining Muslim cavalry then attacked the Byzantine left wing cavalry at rear while they were held frontally by other half of Muslim cavalry, routing them off the battlefield to the north. Muslim right wing now attacked the Byzantine left half of the center at its left flank while Muslim left half of center attacked from front. Vahan noticing the huge cavalry maneuver of the Muslims ordered his cavalry to group together, but was not quick enough; before Vahan could organize his disparate heavy cavalry squadrons, Khalid had wheeled his cavalry back to attack the concentrating Byzantine horses, falling upon them from the front and the flank while they were still moving into formation. The Muslim horsemen were lightly armed and fast versus the disorganized and disoriented Byzantine heavy cavalry that were soon routed and dispersed to the north, leaving the infantry to its fate. With Byzantine cavalry completely routed Khalid turned to Byzantine right half of center which already held the two prong attack of Muslim infantry. Byzantine left half of the center was attacked at its rear by Khalid's cavalry and was finally broken. With the retreat of Byzantine left half of the center a general Byzantine retreat started. Khalid took his cavalry to north to block the northern route of escape. Byzantine retreated west towards Wadi Ruqqad where there was a bridge at Ayn Dhakar for safe crossing across the deep gorges of the ravines of Wadi Ruqqad. Zarrar had already captured the bridge as part of Khalid's plan the night before. A unit of 500 mounted troops were sent through to block this passageway. In fact, this was the route Khalid wanted the Byzantines to retreat along all the time. The Byzantines were surrounded from all ends now. Some fell into the 200-meters deep ravines off the steep slopes, some tried to escape in the waters, only to be smashed on the rocks below and others were killed in their flight. Nevertheless a large number of the soldiers managed to escape the slaughter. Jonah, the Greek informant of the Rashidun army during the Conquest of Damascus died in this battle. Muslims took no prisoners in this battle, although may have captured some during the subsequent pursuit. Theodore Trithurios died in the battlefield, while Niketas managed to escape and reached Emesa, Jabla ibn Abi Laham also managed to escape and later, for a short time, came to terms with the Muslims, but soon to be defected to Byzantine court again.

Aftermath
Immediately after this operation was over, Khalid and his mobile guard moved north to pursue the retreating Byzantine soldiers; he found them near Damascus and attacked. In the ensuing fight the commander-in-chief of the imperial army, the Armenian prince Vahan who had escaped the fate of most of his men at Yarmouk, was killed. Khalid then entered Damascus where he was said to have been welcomed by the local residents, thus recapturing the city.

When news of the disaster reached the Byzantine Emperor Heraclius at Antioch, he was devastated and enraged. He blamed his wrongdoings for the loss primarily referring to his incestuous marriage to his niece Martina. He would have tried to win over the province if he had the resources,, but now had neither the men nor the money to defend the province further, rather he resorted to the cathedral of Antioch where he observed a solemn service of intercession. He summoned a meeting of his advisers at the cathedral and scrutinized the situation. He was told almost unanimously and accepted the fact the defeat was God's decision and a result of the sins of the people of the land including him. Heraclius took to the sea on a ship to Constantinople in the night. It is said that as his ship was set sail, he bade a last farewell to Syria, saying:

"Farewell, a long farewell to Syria, my fair province. Thou art an infidel's (enemy's) now. Peace be with you, O' Syria - what a beautiful land you will be for the enemy. "

Haraclius abandoned Syria with the holy relic of the True Cross which was, along with other relics at Jerusalem were secretly boarded on ship by Parthia of Jerusalem, just to protect it from the invading Arabs. It is said that the emperor had a fear of water. and a pontoon bridge was made for Heraclius to cross the Bosphorous to Constantinople. After abandoning Syria, the Emperor began to concentrate on his remaining forces for the defence of Anatolia and Egypt instead. No efforts were made by the Muslims to capture Anatolia, but it was subjected to annual raids, which devastated the socioeconomic activities of eastern Anatolia. Byzantine Armenia fell to the Muslims in 638ndash39 after which Heraclius created a buffer zone in central Anatolia by ordering all the forts east of Tarsus to be evacuated. In 639ndash642 Muslims invaded and captured Byzantine Egypt, led by Amr ibn al-A'as – who had commanded the right flank of the Rashidun army at Yarmouk.

Evaluation
The Battle of Yarmouk can be seen as an example in military history where an inferior force by superior generalship manages to overcome a superior force.

The Imperial Byzantine commanders allowed their enemy to have the battlefield of his choosing. Even then they were at no critical tactical disadvantage. Khalid knew all along that he was up against a force superior in numbers and, until the last day of the battle, he conducted an essentially defensive campaign suited to his relatively limited resources. When he decided to take the offensive and attack on the final day of battle, he did so with a degree of imagination, foresight and courage that none of the Byzantine commanders ever displayed. Although he commanded a numerically inferior force and needed all the men he could muster, he nevertheless had the confidence and foresight to dispatch a cavalry regiment the night before his assault to seal off a critical path of retreat for the enemy army.

Khalid ibn al-Walid was one of the finest cavalry commanders in history and his use of mounted warriors throughout the battle showed just how well he understood the potentials and strengths of mounted troops. His mobile guard moved quickly from one point to another, always changing the course of events wherever they appeared, and then just as quickly galloping away to change the course of events elsewhere on the field.

Vahan and his Byzantine commanders never dealt with this mounted force effectively. Their own Byzantine cavalry never played a significant role in the battle and were held in static reserve for most of the six days. They never pushed their attacks and even when they obtained what could have been a decisive breakthrough on the fourth day, they were unable to exploit it. There appeared to be a decided lack of resolve among the Imperial commanders, though this may have been caused by difficulties commanding the army because of internal conflict. Moreover, many of the Arab auxiliaries were mere levies, while the Muslim Arab army consisted for a much larger part of veteran troops.

The original strategy of Heraclius, to destroy the Muslim troops in Syria, needed a rapid and quick deployment, but the commanders on the ground never displayed these qualities. Ironically, on the field at Yarmouk, Khalid carried out on a small tactical scale what Heraclius had planned on a grand strategic scale: by rapidly deploying and manoeuvering his forces, Khalid was able to temporarily concentrate sufficient forces at specific locations on the field to defeat the Byzantine troops in detail. Mahan was never able to make his numerical superiority count, partly because of the unfavorable terrain that prevented large-scale deployment. However, at no point did Vahan attempt to concentrate a superior force to achieve a critical breakthrough. Although he was on the offensive 5 days out of the six, his battle line remained remarkably static. This all stands in stark contrast to the very successful offensive plan that Khalid carried out on the final day, when he reorganised virtually all his cavalry and committed them to a grand manoeuvre that won the battle. George F. Nafziger, in his book Islam at war, describes the battle as: Although Yarmouk is little known today, it is one of the most decisive battle in human history...... Had Heraclius's forces prevailed, modern world could be so changed as to be unrecognizable.

Modern sources

 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).
 * Khalid ibn al-Walid, Encyclopædia Britannica (2007).