Arab conquest of the Levant

The Muslim conquest of the Levant (اَلْـفَـتْـحُ الْإٍسْـلَامِيُّ لِـلـشَّـامِ, Al-Faṫṫḥul-Islāmiyyuash-Shām) or Arab conquest of the Levant (اَلْـفَـتْـحُ الْـعَـرَبِيُّ لِـلـشَّـامِ, Al-Faṫṫḥul-ʿArabiyyu Lish-Shām) occurred in the first half of the 7th century, and refers to the conquest of the region known as the Levant or Shaam (شَـام, 'Syria'), later to become the Islamic Province of Bilad al-Sham, as part of the Islamic conquests. Arab Muslim forces had appeared on the southern borders even before the death of prophet Muhammad in 632, resulting in the Battle of Mu'tah in 629, but the real invasion began in 634 under his successors, the Rashidun Caliphs Abu Bakr and Umar ibn Khattab, with Khalid ibn al-Walid as their most important military leader.

Roman Syria
Syria had been under Roman rule for seven centuries prior to the Arab Muslim conquest and had been invaded by the Sassanid Persians on a number of occasions during the 3rd, 6th and 7th centuries; it had also been subject to raids by the Sassanid's Arab allies, the Lakhmids. During the Roman period, beginning after the fall of Jerusalem in the year 70, the entire region (Judea, Samaria, and the Galilee) was renamed Palaestina, subdivided into Diocese I and II. The Romans also renamed an area of land including the Negev, Sinai, and the west coast of the Arabian Peninsula as Palaestina Salutaris, sometimes called Palaestina III or Palaestina Tertia. Part of the area was ruled by the Arab vassal state of the Ghassanids' symmachos. During the last of the Roman-Persian Wars, beginning in 603, the Persians under Khosrau II had succeeded in occupying Syria, Palestine and Egypt for over a decade before being forced by the victories of Heraclius to conclude the peace of 628. Thus, on the eve of the Muslim conquests the Romans (or Byzantines as modern Western historians conventionally refer to Romans of this period) were still in the process of rebuilding their authority in these territories, which in some areas had been lost to them for almost twenty years. Politically, the Syrian region consisted of two provinces: Syria proper stretched from Antioch and Aleppo in the north to the top of the Dead Sea. To the west and south of the Dead Sea lay the province of Palestine. Syria was mostly a Syriac and Hellenized land with some Jewish presence and with a partly Arab population, especially in its eastern and southern parts. The Syriac Christians, Jews and Arabs had been there since pre-Roman times, and some had embraced Christianity since Constantine I legalized it in the fourth century and moved the capital from Italy to Byzantium (renamed Constantinople), from which the name Byzantine is derived.

The Arabs of Syria were people of no consequence until the migration of the powerful Ghassan tribe from Yemen to Syria, who thereafter ruled a semi-autonomous state with their own king under the Romans. The Ghassan Dynasty became one of the honoured princely dynasties of the Empire, with the Ghassan king ruling over the Arabs in Jordan and Southern Syria from his capital at Bosra. The last of the Ghassan kings, who ruled at the time of the Muslim invasion, was Jabla bin Al Aiham.

The Byzantine (Roman) Emperor Heraclius, after re-capturing Syria from the Sassanians, set up new defense lines from Gaza to the south end of the Dead Sea. These lines were only designed to protect communications from bandits, and the bulk of the Byzantine defenses were concentrated in Northern Syria facing the traditional foes, the Sassanid Persians. This defense line had as a drawback that it enabled the Muslims, who emerged from the desert in the south, to reach as far north as Gaza before meeting regular Byzantine troops.

The 7th century was a time of fast military changes in the Byzantine Empire. The empire was certainly not in a state of collapse when it faced the new challenge from Arabia after being exhausted by recent Roman–Persian Wars, but failed completely to tackle the challenge effectively.

Rise of the Caliphate
Muhammad died in June 632, and Abu Bakr was appointed Caliph and political successor at Medina. Soon after Abu Bakr's succession, several Arab tribes revolted against him in the Ridda wars (Arabic for the Wars of Apostasy). The Campaign of the Apostasy was fought and completed during the eleventh year of the Hijri. The year 12 Hijri dawned, on 18 March 633, with Arabia united under the central authority of the Caliph at Medina.

Whether Abu Bakr intended a full-out imperial conquest or not is hard to say; he did, however, set in motion a historical trajectory that in just a few short decades would lead to one of the largest empires in history, starting with a confrontation with the Persian Empire under the general Khalid ibn al-Walid.

Expedition to Syria
After successful campaigns against the Sassanids and the ensuing conquest of Iraq Khalid established his stronghold in Iraq. While engaged with Sassanid forces, confrontation also ensued with the Byzantine Arab clients, the Ghassanids. Tribal contingents were soon recruited to the call from Medinah from all over the Arabian peninsula. Only those who had rebelled during the Ridda wars were excluded from the summons and remained excluded from Rashidun armies until in 636 when Caliph Umar fell short of manpower for the Battle of Yarmouk and the Battle of al-Qādisiyyah. The tradition of raising armies from tribal contingents remained in use until 636, when Caliph Umar organised the army as a state department. Abu Bakr organised the army into four corps, each with its own commander and objective.
 * Amr ibn al-A'as: Objective Palestine. Move on Elat route, then across Valley of Arabah.
 * Yazid ibn Abu Sufyan: Objective Damascus. Move on Tabuk route.
 * Shurahbil ibn Hasana: Objective Jordan. Move on Tabuk route after Yazid.
 * Abu Ubaidah ibn al-Jarrah: Objective Emesa. Move on Tabuk route after Shurahbil.

Not knowing the precise position of the Byzantine army, Caliph Abu Bakr ordered that all corps should remain in touch with each other so that they could help each other if the Byzantines were able to concentrate their army in any sector of operation. In case the corps had to concentrate for one major battle, Abu Ubaidah was appointed Commander-in-Chief of the entire army. In the first week of April 634, the Muslim forces began to move from their camps outside Medina. The first to leave was Yazid's corps, followed by Shurahbil, Abu Ubaidah and Amr, each a day's march from the other. Caliph Abu Bakr walked for a short distance by the side of each corps commander. His parting words which he repeated to each of the corps commanders, were as follows: "In your march be not hard on yourself or your army. Be not harsh with your men or your officers, whom you should consult in all matters. Be just and abjure evil and tyranny, for no nation which is unjust prospers or achieves victory over its enemies. When you meet the enemy turn not your back on him; for whoever turns his back, except to manoeuvre for battle or to regroup, earns the wrath of Allah. His abode shall be hell, and what a terrible place it is! And when you have won a victory over your enemies, don't kill women or children or the aged and do not slaughter beasts except for eating. And break not the pacts which you make. You will come upon a people who live like hermits in monasteries, believing that they have given up all for God. Let them be and destroy not their monasteries. And you will meet other people who are partisans of Satan and worshippers of the Cross, who shave the centre of their heads so that you can see the scalp. Assail them with your swords until they submit to Islam or pay the Jizya. I entrust you to the care of Allah."

Conquest of Syria under Caliph Abu Bakr


Moving to their assigned target beyond Tabouk, Yazid's corps made contact with a small Christian Arab force that was retreating after a skirmish with the Muslim advance guard, after which Yazid made for the Valley of Araba where it meets the southern end of the Dead Sea. As the main Byzantine defence line started from the coastal regions near Ghazahh, Yazid arrived at the Valley of Araba at about the same time as Amr bin Al Aas reached Elat. The two forward detachments sent by the Byzantine army to prevent the entry of Yazid's and Amr's corps, respectively, into Palestine, were easily defeated by them, though they did prevent the Rashidun forces from reaching their assigned objective. Abu Ubaidah and Shurhabil, on the other hand, continued their march, and by early May 634 they reached the region between Bosra and Jabiya. The Emperor Heraclius, having received intelligence of the movements of the Muslim armies from his Arab clients, began to plan countermeasures. Upon Heraclius' orders, Byzantine forces from different garrisons in the north started moving to gather at Ayjnadyn. From here they could engage Amr's corps and maneuver against the flank or rear of the rest of the Muslim corps that were in Jordan and Southern Syria. The strength of the Byzantine forces, according to rough estimates, was about 100,000. Abu Ubaidah informed the Caliph about the preparations made by the Byzantines in the third week of May 634. Because Abu Ubaida didn't have the experience as a commander of military forces in such major operations, especially with the powerful Roman Army, Abu Bakr decided to send Khalid ibn Walid to the Syrian front to command the Muslim army. According to early Muslim chronicles Abu Bakr said: "By Allah, I shall destroy the Romans and the friends of Satan with Khalid Ibn Al Walid."

Khalid was immediately dispatched to the Syrian front. He set out for Syria from Al-Hirah, in Iraq in early June 634, taking with him half his army, about 8000 strong. There were two routes towards Syria from Iraq: one was via Daumat-ul-Jandal, and the other was through Mesopotamia, passing through Raqqa. The Muslim armies in Syria were in need of urgent reinforcement, so Khalid avoided the conventional route to Syria via Daumat ul Jandal, as it was the longer route, and would take weeks to reach Syria. Khalid avoided the Mesopotamia’s route because of the presence of Roman garrisons in Northern Syria and Mesopotamia. To engage them at a time when Muslim armies were being outflanked in Syria was not a wise idea. Khalid selected a shorter route to Syria, an unconventional route passing through the Syrian Desert. He boldly marched his armies through the desert. It is recorded that his soldiers marched for two days without a single drop of water, before reaching a pre-decided water source at an oasis. Khalid thus entered Northern Syria and caught the Byzantines at their right flank. According to modern historians, it was this ingenious strategic maneuver of Khalid, his perilous march through the desert and appearing at the north-eastern front of the Byzantines while they were occupied in tackling the Muslim armies in Southern Syria, that unhinged the Byzantine defences in Syria.

Conquest of Southern Syria
Ain Tamer, Quraqir, Suwa, Arak, and the historical city of Tadmur were first to fall to Khalid. Sukhnah, al-Qaryatayn and Hawarin were captured after the Battle of al-Qaryatayn and the Battle of Hawarin. After dealing with all these cities, Khalid moved towards Damascus, passing through a mountain pass which is now known as Sanita-al-Uqab (Uqab pass) after the name of Khalid's army standard. From here he moved away from Damascus, towards Bosra, the capital of Ghassanid Arab kingdom, a vassal of the Eastern Roman empire. He ordered other Muslim commanders to concentrate their armies, still near the Syrian-Arabian border at Bosra. At Maraj-al-Rahab, Khalid defeated a Ghassanid army of Christian Arabs in a quick battle, called the Battle of Marj-al-Rahit. Meanwhile, Abu Ubaida ibn al-Jarrah, the supreme commander of the Muslim armies in Syria, had ordered Shurhabil ibn Hasana to attack Bosra. The latter laid siege of Bosra with his small army of 4000 men. The Roman and Ghassanid Arab garrison, noticing that this might be the advance guard of the larger Muslim army to come, decided to attack and destroy Shurhabil's army. They came out of the fortified city and attacked Shurhabil, surrounding him from all sides; Khalid reached the arena with his advance guard cavalry and saved the day for Shurhabil. The combined forces of Khalid, Shurhabil and Abu Ubaidah then laid siege to the city of Bosra, which surrendered some time in mid July 634. This effectively ended the Ghassanid Dynasty.

Here Khalid took over the command of the Muslim armies in Syria from Abu Ubaidah, according to the instructions of the Caliph. Massive Byzantine armies were concentrating at Ajnadayn to push the invading armies back to the desert. Early Muslim sources have mentioned its size to be 90,000, while most of the modern historians doubt the figures, but consider this battle to be the key that broke the Byzantine power in Syria. According to the instructions of Khalid all Muslim corps concentrated at Ajnadayn, where they fought a decisive battle against the Byzantines on 30 July 634. The defeat of the Byzantines at the Battle of Ajnadayn left Syria vulnerable to the Muslim invaders. Khalid decided to capture Damascus, the Byzantine stronghold. At Damascus Thomas, son in law of Emperor Heraclius, was in charge. Having received intelligence of Khalid’s march towards Damascus he prepared for the defence of Damascus. He wrote to Emperor Heraclius, who was at Emesa that time, for reinforcements. Moreover, Thomas, in order to get more time for preparation of a siege, sent armies to delay or if possible halt Khalid’s march to Damascus. One of these armies was defeated at the Battle of Yaqusa in mid-August 634 near Lake Tiberias 145 kilometres (90 mi) from Damascus. Another army that tried to halt the Muslim advance to Damascus was defeated in the Battle of Maraj as Saffer on 19 August 634. These engagements delayed Khalid's advance and gave Thomas enough time to prepare for a siege. Meanwhile, a reinforcement reached the city, which Heraclius had dispatched after hearing the bad news of Ajnadyn. But before another regiment of Heraclius could reach Damascus, Khalid had already laid siege to Damascus. Khalid reached Damascus on the 20th of August, and besieged the city. To isolate the city from the rest of the region Khalid placed detachments south on the road to Palestine and in the north at the Damascus-Emesa route, and several other smaller detachments on routes towards Damascus. Heraclius reinforcement was intercepted and routed at the Battle of Sanita-al-Uqab 30 kilometres (20 mi) from Damascus. Khalid's forces withstood three Roman sallies that tried to break the siege. Khalid finally attacked and conquered Damascus on 18 September 634 after a 30 days siege, although according to some sources the siege lasted for four or six months. Heraclius, having received the news of the fall of Damascus, left for Antioch from Emesa. A peace agreement was made: the citizens were given peace on the terms of annual tribute and the Byzantine army was given a three-day peace period to go as far as they could. After the deadline of three days was over, the Muslim cavalry under Khalid's command, attacked the Roman army, catching up on them using an unknown shortcut, at the Battle of Maraj-al-Debaj, 305 km north of Damascus. Abu Bakr died during the siege of Damascus, and Umar became the new Caliph. He dismissed his cousin Khalid ibn al-Walid from command and appointed Abu Ubaidah ibn al-Jarrah as the new commander in chief of the Islamic army in Syria. Abu Ubaidah got the letter of his appointment and Khalid's disposal during the siege, but he delayed the announcement until the city was conquered.

Dismissal of Khalid from command
On 22 August 634, Abu Bakr, the first caliph, died, having made Umar his successor. Umar's first move was to relieve Khalid from command and appointing Abu Ubaidah ibn al-Jarrah as the new commander in chief of the Islamic army. Later on, Khalid gave a pledge of loyalty to the new Caliph and kept on serving as an ordinary commander under Abu Ubaidah. He is reported to have said:

There was inevitably a slowdown in the pace of military operations, as Abu Ubaidah moved more slowly and steadily. The conquest of Syria continued under him. Abu Ubaidah, being an admirer of Khalid, made him commander of the cavalry and relied heavily on his advice during the whole campaign.

Conquest of Central Levant
Soon after the appointment of Abu-Ubaidah as commander in chief, he sent a small detachment to the annual fair of Abu-al-Qudas (Mass (liturgy)), held at Ablah, near Zahlé 50 km east of Beirut. There was a Byzantine and Christian Arab garrison nearby, but the size of the garrison was miscalculated by the Muslim informants. The garrison quickly encircled the small Muslim detachment, but before it was completely destroyed, Khalid came to the rescue of the Muslim army. Abu Ubaidah, having received new intelligence, had sent Khalid. Khalid reached the battlefield and defeated the garrison on 15 October 634 and returned with tons of looted booty from the fair and hundreds of Roman prisoners. By capturing central Syria, the Muslims had given a decisive blow to the Byzantines. The communication between Northern Syria and Palestine was now cut off. Abu Ubaidah decided to march to Fahl, which is about 150 metres (500 ft) below sea level, where a strong Byzantine garrison and survivors of the Battle of Ajnadayn were present. The region was crucial because from here the Byzantine army could strike eastwards and cut Muslim’s communications with Arabia. Moreover, with this large garrison at their rear Palestine could not be invaded. These were the reasons why the Muslim army moved against Fahl. Khalid commanded the advance guard and reached Fahl first and found that the plains were flooded by the Byzantines who had blocked the River Jordan. The Byzantine army was eventually defeated at the Battle of Fahl on 23 January 635.

Conquest of Palestine
Next, the Muslim armies consolidated their conquest of the Levant as Shurhabil and Amr went deeper into Palestine after the decisive Battle of Fahl. Bet She'an surrendered after a little resistance followed by the surrender of Tiberias in February 635. Caliph Umar, after having received the position and strength of the Byzantine army in Palestine, wrote detailed instructions to corps commanders in Palestine and ordered Yazid to capture the Mediterranean coast. The corps of Amr and Shurhabil accordingly marched against the strongest Byzantine garrison in Ajnadyn and defeated them in the Second Battle of Ajnadyn after which the two corps separated, with Amr moving to capture Nablus, Amawas, Jaffa, Haifa, Gaza and Yubna in order to complete the conquest of all Palestine, while Shurahbil moved against the coastal towns of Acre and Tyre. Yazid advanced from Damascus to capture the ports of Sidon, Arqa, Byblos and Beirut. By 635 CE, Palestine, Jordan and Southern Syria, with the exception of Jerusalem and Caesarea, were in Muslim hands. On the orders of Caliph Umar, Yazid next besieged Caesarea, which was lifted but resumed after the Battle of Yarmouk until the port fell in 640.

Battles for Emesa and Second Battle of Damascus
After the battle, which proved to be the key to Palestine and Jordan, the Muslim armies split up. Shurhabil and Amr’s corps moved south to capture Palestine, while Abu Ubaidah and Khalid with a relatively larger corps moved north to conquer Northern Syria. While the Muslims were occupied at Fahl. Heraclius, sensing an opportunity, quickly sent an army under General Theodras to recapture Damascus, where a small Muslim garrison was left. Shortly after Heraclius dispatched this new army, the Muslims, after having won the Battle of Fahl, were on their way to Emesa. In the meantime, the Byzantine army split into two, one deployed at Maraj al Rome (Beqaa Valley) led by Schinos; the other, commanded by Theodras, stationed to the west of Damascus (Al-Sabboura region). During the night, Theodras went with his army towards Damascus to launch a surprise attack on the Muslim garrison there. Khalid's spy informed him about the move and Khalid, having received permission from Abu Ubaidah, galloped towards Damascus with his mobile guard. While Abu Ubaidah fought and defeated the Roman army in the Battle of Maraj-al-Rome, Khalid moved to Damascus with his cavalry and attacked and defeated Theodras there. A week later, Abu Ubaida himself moved towards Heliopolis, where the great Temple of Jupiter stood. Helipolis surrendered to Muslim rule after little resistance and agreed to pay tribute in May 636. Abu Ubaidah sent Khalid straight towards Emesa. Emesa and Chalcis offered a peace treaty for a year. Abu Ubaidah accepted the offer and rather than invading districts of Emesa and Chalcis, he consolidated his rule in conquered land and captured Hamah, Maarrat al-Nu'man. Having mustered sizeable armies at Antioch, Heraclius sent them to reinforce strategically important areas of Northern Syria, like Emesa and Chalcis. With the arrival of the Byzantine army in the city, the peace treaty was violated; Abu Ubadiah and Khalid then marched to Emesa. A Byzantine army that halted Khalid's advance guard was defeated. The Muslims besieged Emesa which was finally conquered in March 636 CE after two months of siege.

Battle of Yarmouk


After capturing Emesa, the Muslims moved north to capture the whole of Northern Syria. Khalid took his mobile guard, acting as an advance guard, to raid Northern Syria. At Shaizer Khalid intercepted a convoy taking provisions for Chalcis. The prisoners were interrogated and informed him about Emperor Heraclius' ambitious plan to take back Syria. They told him that an army possibly two hundred thousand (200,000) strong would soon arrive to recapture their territory. Khalid immediately ended the raid.

After his past experiences Heraclius now avoided pitch battle with the Muslim army. His plans were to send massive reinforcements to all the major cities and isolate the Muslim corps from each other and then to separately encircle and destroy the Muslim armies.

Part of his plans was to coordinate his attacks with those of Yazdgerd III. In 635 Yazdgerd III, the emperor of Sassanid Persian Empire, had sought an alliance with Heraclius. Heraclius married off his daughter (according to traditions, his granddaughter) Manyanh to Yazdegerd III, an old Roman tradition to show alliance. While Heraclius prepared for a major offense in the Levant, Yazdegerd was supposed to mount a counterattack on his front in Iraq. This was supposed to be a well coordinated attack by both emperors, Heraclius in the Levant and Yazdegerd in Iraq, to annihilate the power of their common enemy Caliph Umar. However, it was not meant to be. Umar probably had intelligence of this alliance, and started peace negotiations with Yazdegerd III, apparently inviting him to join Islam. When Heraclius launched his offense in May 636, Yazdegerd, probably owing to the exhausted conditions of his government, could not coordinate with the Heraclian offense and a would be decisive plan missed the mark. While Umar won a decisive victory at Yarmouk against Heraclius, 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.

Five massive armies were launched in June 636 CE to recapture Syria. Khalid, having understood Heraclius' plan, feared that the Muslim armies would become isolated and then piecemeal destroyed. He thus suggested Abu Ubaidah in a council of war to draw all the Muslim armies at one place to give a decisive battle to the Byzantines. Abu Ubaidah listened to Khalid's advice and ordered all the Muslim armies in Syria to evacuate the conquered land and concentrated them at Jabiya. This maneuver of Khalid gave a decisive blow to Heraclius' plan, since he wished not to engage his troops in an open battle with the Muslims, where the Muslims could use their light cavalry effectively. From Jabiya, again on Khalid’s suggestion, Abu Ubaidah ordered the Muslim troops to withdraw to the Plain of the Yarmouk River, where cavalry could be used effectively. While the Muslim armies were gathering at Yarmouk, Khalid intercepted and routed the Byzantine advance guard. This was to ensure the safe retreat of Muslims from the conquered land. The Muslim armies reached the plain in July 636 CE. A week or two later, around mid July, the Byzantine army arrived. The Byzantine commander in chief, Vahan, sent Christian Arab troops of Ghassanid king Jabala to check the strength of the Muslims. Khalid’s mobile guard defeated and routed the Christian Arabs; this was the last action before the battle started. For one month negotiations continued between the two armies and Khalid went to meet Vahan in person at the Byzantine camp. Meanwhile, Muslims received reinforcements sent by Caliph Umar. Abu Ubaidah, in a council of war, transferred the command of the Muslim army to Khalid, who acted as a field commander in the battle and was the mastermind behind the annihilation of Byzantine army. Finally on 15 August the Battle of Yarmouk was fought, that lasted for 6 days and ended in a major defeat for the Byzantines. This battle and subsequent clean-up battles, forever ended Byzantine domination of the Levant.

Capturing Jerusalem
With the Byzantine army shattered and routed, the Muslims quickly recaptured the territory that they had conquered prior to Yarmouk. Abu Ubaida held a meeting with his high command officers, including Khalid, to decide on future conquests. They decided to conquer Jerusalem. The Siege of Jerusalem lasted four months after which the city agreed to surrender, but only to caliph Umar Ibn Al Khattab in person. Amr-bin al-Aas suggested that Khalid should be sent as caliph, because of his very strong resemblance with Caliph Umar. But Khalid was recognized and Caliph Umar Ibn Al-Khattab had to come himself to accept the surrender of Jerusalem on April 637 CE. After Jerusalem, the Muslim armies broke up once again. Yazid's corps came to Damascus and captured Beirut. Amr and Shurhabil’s corps went to conquer the rest of Palestine, while Abu Ubaidah and Khalid ahead of a 17,000 strong army moved north to conquer the whole of Northern Syria.

Conquest of Northern Syria
With Emesa already in hand, Abu Ubaidah and Khalid moved towards Chalcis, which was strategically the most significant fort of the Byzantines. Through Chalcis the Byzantines would be able to guard Anatolia, Heraclius' homeland Armenia and their Asian zone’s capital Antioch. Abu Ubaidah sent Khalid with his cavalry elite, the mobile guard, towards Chalcis. The fort was guarded by Greek troops under their commander Menas, who is reported to be of high prestige, second only to the Emperor himself. Menas, diverting from conventional Byzantine tactics, decided to face Khalid and destroy the leading elements of Muslim army before the main body could join them at Hazir 5 kilometres (3 mi) east of Chalcis. The battle fought is known as the Battle of Hazir, which even forced Caliph Umar to praise Khalid’s military genius. Umar is reported to have said:

Abu Ubaidah soon joined Khalid at the virtually impregnable fort of Chalcis. The fort surrendered some time in June 637. With this strategic victory the territory north of Chalcis lay open to the Muslims. Khalid and Abu Ubaidah continued their march northward and laid siege to Aleppo, which was captured after fierce resistance from desperate Byzantine troops in October 637 CE. The next objective was the splendid city of Antioch, the capital of the Asian zone of the Eastern Roman empire. Before marching towards Antioch, Khalid and Abu Ubaidah decided to isolate the city from Anatolia. They accordingly sent detachments north to eliminate all possible Byzantine forces and captured a garrison town of Azaz 50 kilometres (30 mi) from Aleppo; from there Muslims attacked Antioch from the eastern side. In order to save the empire from annihilation, a desperate battle was fought between the Muslim army and that of the defenders of Antioch, popularly known as the Battle of Iron bridge. The Byzantine army was composed of the survivors of Yarmouk and other Syrian campaigns. After being defeated, the Byzantines retreated to Antioch and the Muslims besieged the city. Having little hope of help from the Emperor, Antioch surrendered on the 30th of October 637 CE, under the condition that all Byzantine troops would be given safe passage to Constantinople. Abu Ubaidah sent Khalid towards the north and he himself marched to the south and captured Latakia, Jablah and Tartus and the coastal areas west of anti-lebonan hills. Khalid moved north and raided territory up to as far as Kızılırmak River in Anatolia. Emperor Heraclius had already left Antioch for Edessa before the arrival of the Muslims. He arranged for the necessary defenses in Jazirah and Armenia and left for his capital Constantinople. On his way to Constantinople he had a narrow escape when Khalid after capturing Marash was heading south towards Manbij. Heraclius hastily took the mountainous path and passing through the Cilician gates is reported to have said:

After the devastating defeat at Yarmouk, his empire was extremely vulnerable to a Muslim invasion. With few military resources left he was no longer in a position to attempt a military comeback in Syria. To gain time for the preparation of the defense of the rest of his empire Heraclius needed the Muslims occupied in Syria. He thus sought help from the Christians (including Arab Christians) of Jazirah mainly from Circesium and Hīt who mustered up a large army and marched against Emesa, Abu Ubaidah’s headquarter. Abu Ubaidah withdrew all his forces from Northern Syria to Emesa, and the Christians laid siege to Emesa. Khalid was in favor of an open battle outside the fort, but Abu Ubaidah sent the matter to Caliph Umar who sent a detachment of Muslim armies from Iraq to invade Jazirah, homeland of the invading Christians, from three different routes. Moreover, another detachment was sent to Emesa from Iraq under Qa’qa ibn Amr, a veteran of Yarmouk, who was sent to Iraq for the Battle of al-Qādisiyyah. Umar himself marched from Madinah ahead of 1,000 men.

In 638, Muslims attacked Hīt which was well fortified, thus, they left a fraction of the army to impose a siege on the city, while the rest would go after Circesium. When the Christians received the news of the Muslim invasion of their homeland, they abandoned the siege and hastily withdrew to Jazirah. At this point Khalid and his mobile guard came out of the fort and devastated their army by attacking them from the rear. This act of Jazirah's Christians was followed by fierce measures from the Caliphate, and Jazirah, the last base of the Eastern Roman empire in the Middle East was captured.

On the orders of Caliph Umar, Sa'd ibn Abi Waqqas, commander of the Muslim army in Iraq, sent an army under Iyad ibn Ghanm to conquer the region between the Tigris and the Euphrates up to Urfa. In 639–640, Raqqa fell into Muslim hands, followed by most of Jazirah which surrendered peacefully and agreed to pay Jizya.

Campaigns in Armenia and Anatolia


After the battle Umar ordered the conquest of Jazirah which was completed by 640 CE. After the conquest of Jazirah Abu Ubaidah sent Khalid and Iyad ibn Ghanm (conqueror of Jazirah) to invade Byzantine territory north of Jazirah. They marched independently and captured Edessa, Amida, Malatya and the whole of Armenia up to Ararat and raided Northern and central Anatolia. Heraclius had already abandoned all the forts between Antioch and Tartus to create a buffer zone or no man's land between the Muslim controlled areas and main land Anatolia.

Caliph Umar for the time being stopped his armies invading deeper into Anatolia and rather ordered Abu Ubaidah, now governor of Syria, to consolidate his rule in Syria.

The dismissal of Khalid from the army and a drought followed by a plague the year after were factors why the Muslim armies didn't eventually invade Anatolia. The expedition to Anatolia and Armenia marked the end of the military career of Khalid.

Under Caliph Uthman's reign


During the reign of Caliph Uthman, Constantine III decided to recapture the Levant, which had been lost to the Muslims during Umar’s reign. A full-scale invasion was planned and a large force was sent to reconquer Syria. Muawiyah I, the governor of Syria, called for reinforcements and Uthman ordered the governor of Kufa to send a contingent, which together with the garrison of Syria defeated the Byzantine army in Northern Syria.

In 645–646, Sufyan bin Mujib Al-Azdi, appointed by Muawiyah, managed to seize Tripoli to eventually capture the last Byzantine stronghold on the Levantine coast.

Uthman gave permission to Muawiyah to build a navy. From their base in Syria, the Muslims used this fleet to capture Cyprus in 649 and Crete and then Rhodes and the launching of annual raids into Western Anatolia thwarted the Byzantines from making any further attempts to recapture Syria. In 654–655, Uthman ordered the preparation of an expedition to capture the capital of the Eastern Roman empire, Constantinople, but due to unrest in the empire that grew in 655 and resulted in his assassination, the expedition was delayed for decades only to be attempted unsuccessfully under the next dynasty of Ummayad rulers.

Administration under Rashidun Caliphate
The new rulers divided Syria into four districts (junds): Jund Dimashq (Damascus), Jund Hims, Jund al-Urdunn (Jordan), and Jund Filastin (Palestine) (to which a fifth, Jund Qinnasrin, was later added) and the Arab garrisons were kept apart in camps, and life went on much as before for the local population. The Muslims tolerated the Jews and Christians. Nestorian and Jacobite Christians had better treatment under the Muslims than they did under the Byzantines. The taxes instituted were the kharaj – a tax that landowners and peasants paid according to the productivity of their fields – as well as the jizya – paid by non-Muslims in return for protection under the Muslim state and exemption from military service. The Byzantine civil service was retained until a new system could be instituted; therefore, Greek remained the administrative language in the new Muslim territories for over 50 years after the conquests.

Rise of the Umayyads
When the first civil war broke out in the Muslim empire as a result of the murder of Uthman and the nomination of Ali as caliph, the Rashidun Caliphate was succeeded by the new dynasty of Umayyad with Syria as its core and Damascus its capital for the next century to come.