Arab–Byzantine wars
The Arab-Byzantine wars stretched across four centuries, from the 630s to the late 11th century, and reshaped the map of the known world. At stake were Egypt, Syria, North Africa, the coasts of Sicily, and ultimately the city of Constantinople itself. How did a series of conflicts beginning in Arabia end up determining the fate of Western Europe? What brought the mightiest empire of the late ancient world to near collapse, only for it to come roaring back a generation later? Those questions run through every chapter of this story.
Emperor Heraclius restored the True Cross to Jerusalem in 629, capping a hard-won victory over the Persians. It was the high-water mark of Byzantine power. Yet as the historian George Liska would later observe, the unnecessarily prolonged Byzantine-Persian conflict had opened the way for Islam. Both the Byzantine and Sasanian empires emerged from their wars exhausted and vulnerable, and the recurring outbreaks of bubonic plague known as the Plague of Justinian had compounded that weakness. Within a few years, according to the historian Howard-Johnston, what arrived from Arabia could only be likened to a human tsunami. In the late 620s, the Prophet Muhammad had already unified much of Arabia through conquest and alliances with neighboring tribes. A confrontation at the Battle of Mu'tah, triggered by the murder of Muhammad's ambassador at the hands of the Ghassanids, a Byzantine vassal kingdom, gave the first taste of direct friction between the two worlds. Muhammad died in 632 and was succeeded by Abu Bakr, the first Caliph with undisputed control of the entire Arabian Peninsula following the Ridda Wars, which consolidated a powerful Muslim state throughout the peninsula.
Khalid ibn al-Walid captured Damascus in 634, the same year that a Rashidun army won a decisive victory near Ajnadayn. Emperor Heraclius had fallen ill and could not personally lead his armies to resist the Arab advance into Syria and Roman Palestine. The Byzantines marshaled their maximum available forces under commanders including Theodore Trithyrius and the Armenian general Vahan, but at the Battle of the Yarmuk in 636 the Muslims studied the ground carefully, lured the Byzantines into pitched battle, and used the deep valleys and cliffs to turn the encounter into what one source calls a catastrophic death-trap. Heraclius departed Antioch for Constantinople leaving behind, according to the 9th-century historian Al-Baladhuri, the exclamation: "Peace unto thee, O Syria, and what an excellent country this is for the enemy." Jerusalem was surrendered by Patriarch Sophronius in April 637 after a long siege. Antioch fell in late 637, and in December 639 Muslim forces departed Palestine to invade Egypt. With 3,500-4,000 troops, the general 'Amr ibn al-A'as crossed into Egypt at the end of 639 or the beginning of 640. He was progressively reinforced, notably by 12,000 soldiers under Zubayr ibn al-Awwam. Alexandria was given up by the Byzantines in September 642. The loss of Egypt mattered beyond territory alone: it deprived the Byzantines of their principal wheat supply, causing food shortages across the empire and weakening its armies in the following decades. Between 643 and 644, 'Amr completed the conquest of Cyrenaica, and Cyprus and Crete were captured in 653.
In 649 Mu'awiya ibn Abi Sufyan set up a navy manned by Monophysite Christian, Copt, and Jacobite Syrian Christian sailors along with Muslim troops, a deliberate answer to Byzantine domination of the sea. At the Battle of the Masts in 655, this young Muslim fleet destroyed 500 Byzantine ships and came close to killing Emperor Constans II, cracking open the Mediterranean, hitherto described as a Roman lake, to Arab expansion. In 647 a Rashidun army under Abd Allah ibn Sa'd invaded the Byzantine Exarchate of Africa, conquering Tripolitania and pushing as far as Sufetula, some 150 miles south of Carthage. When the self-proclaimed Emperor of Africa Gregory was killed, his successor Gennadius promised the Arabs an annual tribute of roughly 300,000 nomismata in exchange for their withdrawal. Under the Umayyad Caliphate, which succeeded the Rashidun in 661, the conquest deepened. A vanguard of 10,000 Arabs under Uqba ibn Nafi established Kairouan in 670 as a base for further operations; Kairouan would become the capital of the Islamic province of Ifriqiya and one of the main centers of Arab-Islamic religious life in the Middle Ages. Uqba pressed all the way to the Atlantic shore but was turned back near Tangier by a figure who entered both history and legend as Count Julian. Carthage itself was conquered and destroyed between 695 and 698, stripping the Byzantines of their last major stronghold in the west and giving the Arabs a fleet based in Tunisia that now challenged Byzantine control of the western Mediterranean.
By 670, the Muslim fleet had reached the Sea of Marmara and wintered at Cyzicus. Four years later a massive Arab fleet returned to Cyzicus and launched raids against the Byzantine coasts almost at will. In 676 Mu'awiya sent an army to invest Constantinople by land, beginning the first Arab siege of the city. Constantine IV (r. 661-685) used a new weapon invented by a Christian refugee from Syria named Kallinikos of Heliopolis: Greek fire. The incendiary substance decisively defeated the Umayyad navy in the Sea of Marmara, forcing the siege's end in 678. Among those who died during the siege was Abu Ayyub al-Ansari, the standard bearer of Muhammad and the last of his companions; his tomb is considered one of the holiest sites in Istanbul to Muslims today. The second and larger siege began in July 717 under the Umayyad prince and general Maslama ibn Abd al-Malik. The sources place the Caliphate's force at some 120,000 men and 1,800 ships. The emperor Leo the Isaurian, who had seized the throne only in March 717, concluded an alliance with the Bulgar khan Tervel, who agreed to harass the invaders from the rear. Greek fire again defeated the Arab fleet, and the army, forced to extend the siege through winter, suffered severe casualties from cold and starvation. New Arab fleets sent in spring from Africa and Egypt lost large numbers of sailors who defected, most of them Christians. Land reinforcements were ambushed and defeated in Bithynia. The siege was abandoned on the 15th of August 718. On its return, the Arab fleet suffered further losses to storms and an eruption of the volcano of Thera.
After 718 the border hardened along the Taurus and Anti-Taurus mountain ranges, and the contested strip between them, known in Arabic as al-Dawaahi and in Greek as ta akra, emptied of inhabitants through constant warfare. On the Arab side, Cilician cities including Adana, Mopsuestia, and Tarsus were refortified and resettled under the early Abbasids. On the Byzantine side, the themata system established by Constans II gave the empire a durable defensive skeleton, settling old field armies on land and tying military service to local territories. The raiding pattern quickly became ritualized. One or two summer expeditions, organized as the "expedition of the left" launched from the Cilician thughur and the usually larger "expedition of the right" launched from Malatya, struck into Anatolia each year. Caliph Harun al-Rashid (r. 786-809) was the most energetic of the early Abbasid rulers in these campaigns: he stationed himself at Raqqa near the frontier, added a second defensive line north of Syria called the al-'Awasim, and was reputed to alternate years between leading the hajj to Mecca and leading campaigns into Anatolia, including the largest Abbasid expedition on record, assembled in 806. Despite his hostility, the period also saw far more regular diplomatic contact: embassies and letters between the Abbasid court and Constantinople grew markedly more common than they had been under Umayyad rule.
At the Battle of Lalakaon in 863, during the reign of Michael III, the Byzantine general Petronas routed an Abbasid invasion force under Umar al-Aqta, killing Umar and annihilating the remnants of his army in subsequent clashes. News of the defeats sparked riots in Baghdad and Samarra. The Macedonian dynasty, emerging in 867, brought religious peace and a reunified leadership just as the Abbasid caliphate was splintering. Basil I allied with the Holy Roman Emperor Louis II, and their combined effort drove the Arabs from Bari in 871. Under John Kourkouas, Byzantine forces conquered the Emirate of Melitene and advanced into Armenia in the 930s. Crete was reconquered in 961. Nikephoros II Phokas then took Cilicia and northern Syria, sacking Aleppo, before his nephew and successor John I Tzimiskes pushed south toward Jerusalem, halted only by his death in 976. Basil II launched a counter-campaign in Syria in 995, relieving Aleppo, seizing control of the Orontes valley, and recovering Antioch, seat of its own patriarchate. The historian Piers Paul Read wrote that by 1025, Byzantine land stretched from the Straits of Messina and the northern Adriatic in the west to the River Danube and Crimea in the north, and to the cities of Melitene and Edessa beyond the Euphrates in the east. The empire would hold those eastern territories for the next 110 years until 1078, when the Seljuk Turks reversed what centuries of Arab-Byzantine warfare had settled.
The Iconoclast controversy, which Leo III launched formally in 730 with a ban on religious images at court, can be traced in part to a conviction that the empire had lost divine favor amid the Arab onslaught. The controversy weakened Byzantium and drove a wedge between the Patriarch of Constantinople and the Bishop of Rome. That schism pushed the Latin church, in the words of the sources, into the arms of the Franks. Scholars have argued that Charlemagne was an indirect product of Muhammad, captured in the stark formula: the Frankish Empire would probably never have existed without Islam, and Charlemagne without Mahomet would be inconceivable. Meanwhile, Mediterranean trade between Muslim southern and eastern shores and Christian northern shores nearly collapsed: the historian Kennedy observed that in antiquity and again in the high Middle Ages the voyage from Italy to Alexandria was commonplace, but in early Islamic times the two regions were so remote that even the most basic information was unknown. That isolation gave enormous momentum to feudalism and economic self-sufficiency in western Europe. Among the documentary sources historians must still contend with, Walter Emil Kaegi cautions that both Arabic and Byzantine traditions carry bias: the Byzantine chronicles of Theophanes and Nicephorus are short and terse, and Byzantine accounts tend to deflect blame for the initial collapse away from Heraclius himself. The Acritic songs, the sermons of Sophronius and Anastasius Sinaita, the poetry of George of Pisidia, and military manuals including the Strategikon of Maurice from the early 7th century preserve fragments found nowhere else, a reminder that the full story of these wars is still being pieced together.
Common questions
When did the Arab-Byzantine wars begin and end?
The Arab-Byzantine wars began in the 630s with the first Rashidun raids into Byzantine Syria and continued through the 11th century. The Byzantine recovery under the Macedonian dynasty and the final loss of eastern gains to the Seljuk Turks in 1071 marks the conventional end of the conflict.
What was Greek fire and how did it affect the Arab sieges of Constantinople?
Greek fire was an incendiary weapon invented by Kallinikos of Heliopolis, a Christian refugee from Syria. It was used by Constantine IV to decisively defeat the Umayyad navy in the Sea of Marmara during the first siege in 678, and again by Leo III to break the second siege, which ended on the 15th of August 718.
Why did the Arab-Byzantine wars lead to the rise of Charlemagne?
The wars severed Mediterranean trade and drove the Papacy away from Byzantium, which was no longer able to protect Rome while fighting for its own survival. This pushed the Latin church toward the Franks; scholars have argued that the Frankish Empire would probably never have existed without Islam, making Charlemagne an indirect product of Muhammad.
How did the Arabs conquer Egypt during the Arab-Byzantine wars?
The general 'Amr ibn al-A'as crossed into Egypt at the end of 639 or the beginning of 640 with 3,500-4,000 troops, later reinforced by 12,000 soldiers under Zubayr ibn al-Awwam. Alexandria fell by September 642, extinguishing Byzantine rule in Egypt and depriving the Byzantines of their principal wheat supply.
What role did the Battle of the Yarmuk play in the Arab-Byzantine wars?
The Battle of the Yarmuk in 636 was the decisive engagement that opened Syria to Muslim conquest. Muslim forces lured the Byzantines into pitched battle and used the deep valleys and cliffs to turn the fight into a catastrophic defeat, after which Heraclius withdrew from Antioch and Syria passed out of Byzantine control.
How did the Byzantine Empire recover territory during the Arab-Byzantine wars?
The Byzantine resurgence began in earnest at the Battle of Lalakaon in 863, when the general Petronas defeated and killed the Abbasid commander Umar al-Aqta. Under the Macedonian dynasty, the Byzantines reconquered Crete in 961, took Cilicia and northern Syria under Nikephoros II Phokas, and restored Antioch under Basil II, who by 1025 presided over an empire stretching from the Straits of Messina to Edessa beyond the Euphrates.
All sources
17 references cited across the entry
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- 9bookA History of ByzantiumTimothy E. Gregory — John Wiley & Sons — 2011
- 11bookThe Medieval SiegeJim Bradbury — Boydell & Brewer — 1992
- 14bookA Short History of ByzantiumJohn Julius Norwich — Penguin — 1998
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- 17bookByzantine Military Rhetoric in the Ninth Century: A Translation of the Anonymi Byzantini Rhetorica MilitarisGeorgios Theotokis et al. — Taylor & Francis — 2021
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