The Umayyad invasions of Asia Minor, from 720 until the end of the reign of Byzantine Emperor Leo III, were a series of nearly annual campaigns conducted by the Umayyad Caliphate against the Byzantine territories in Asia Minor. Mostly initiated under the leadership of Caliph Hisham ibn Abd al-Malik, these expeditions were conducted by several notable personalities of the Umayyad Al-Thughur, including three of Abd al-Malik's sons Mu'awiya, Maslama and Sulayman ibn Hisham, and occurred both by land and sea. Although the Umayyad invasions continued to have extremely destructive effects, including the sacking of a number of forts and cities, these attacks took place during a period of increasing Byzantine military power over the course of Leo's reign. Consequently, these Umayyad attacks were met with stiffening resistance from the Byzantine thematic and tagmatic forces and had varying outcomes, before culminating in a significant defeat for the caliphate in 740 at the battle of Akroinon.
Background and strategies used
For much of the reign of Emperor Leo III, the Byzantine Empire had been in conflict with the Umayyad Caliphate. Although Leo had won a famous victory at Constantinople at the beginning of his reign, the Umayyad attacks into Anatolia did not abate for long. The sawa'if raids were resumed and pursued vigorously by the Umayyads from 720 onwards. These incursions mainly emerged from two directions, with the route into Anatolia from Tarsus being termed "the left" and the route from Upper Mesopotamia via Melitene labelled "the right". When sufficient resources were dedicated to sawa'if campaigns, separate Umayyad armies attacked Asia Minor simultaneously from both the left and right directions to raid a wider area.
By the 740s, the repeated Umayyad attacks into Anatolia, and less frequent Byzantine counterraids, had resulted in populations being resettled increasingly further away from the frontier regions, forming a no man's land between the empire and caliphate, known as the Al-Awasim. The Byzantines steadily adapted their counterstrategies to mitigate the extent of the devastation sawa'if attacks could inflict. Due to the prowess and numbers of Umayyad invasion forces, the Byzantines typically hesitated to meet them in direct battle, and instead relied on a defensive apparatus centred around fortified strongpoints. Leo III adopted a policy of strengthening both the forts near the frontier and the thematic headquarters further into the interior of Anatolia. With sufficient warnings of an enemy advance, these positions could be reinforced with troops, while non-combatant civilians could be evacuated in order to reserve supplies for the garrison during a siege. When sufficiently prepared, these forts and cities acted as force multipliers for outnumbered Byzantine detachments, and the capture of such positions could be a long and difficult endeavour, even for substantial Umayyad armies, which were tied in place to limit the damage they could inflict in other regions. The Byzantines also employed scorched earth methods to frustrate Umayyad attacks. As a result, the Umayyads were gradually forced to travel further into Asia Minor to find lucrative targets to plunder, and overextension could hinder their ability to capture settlements, and potentially make their armies vulnerable to attacks by Byzantine field forces. The fighting between Byzantium and the Caliphate thus assumed the form of a war of attrition.
Umayyad attacks continue
720–721
In 720/21, an Umayyad force under Al-Walid ibn Hisham al-Mu'ayti invaded Byzantine territory and advanced as far west as Pisidian Antioch. The Arabs attacked the city, but the operation ended in failure, with the withdrawal of al-Mu'ayti's forces. An Umayyad incursion into Sophene, led by Umar ibn Hubayra in the same year, achieved some success, gaining a victory in a battle or siege at an unspecified location, taking 700 captives. In 721, an Umayyad force, under al-Abbas ibn al-Walid, attacked Byzantine holdings in western Cilicia. Al-Walid was able to capture Dalisandos, but his own army sustained very heavy casualties before the fort fell. Al-Walid returned to Umayyad territory, having reportedly captured 20,000 people in the course of the campaign.
However, these Umayyad invasions were counteracted by renewed offensive operations launched by the Byzantine navy. In 721, a Byzantine fleet sailed southwards, targeting the economic hub of Umayyad Egypt. This seaborn raid was successful, and the Byzantines devastated significant parts of the coastline.
722–723
In 722, Abd al-Rahman ibn Sulayman led an army into Western Asia Minor, while the former governor of Medina, Uthman ibn Hayyan al-Murri, campaigned near the Byzantine - Umayyad frontier further east. Neither attack had notable achievements. A more successful invasion was conducted by Marwan ibn Muhammad the in the following year of 723. Detailed descriptions by the sources have not survived, but Marwan captured the fortress of Kamacha and then advanced into Cappadocia, where he took the city of Iconium.
724 One of the commanders leading Umayyad incursions in 724 was Sa'id ibn Abd al-Malik. His forces included significant numbers of Syrian troops. His expedition however was met with greater resistance by the Byzantine thematic forces than before. At an unknown location, a Byzantine army won a victory over Abd al-Malik and forced him to withdraw. The Umayyads sustained heavy casualties from this defeat, and during the retreat the Byzantines managed to cut off an Arab detachment under Kathir ibn Rabi'a and annihilated it, though Rabi'a himself was able to escape with a few of his men. This event was followed by an infamous incident, wherein the Byzantines dismembered over 1,000 Umayyad soldiers, likely prisoners taken in the fighting.
Another Umayyad incursion in 724, led by Marwan ibn Muhammad and Sa'id ibn Hisham, was met with more success. The Arabs campaigned against Byzantine frontier defences near Melitene, and struck toward the fort of Nuwasa, a location on the Upper Euphrates. The Umayyads were able to catch the defenders by surprise, before significant numbers of non-combatant civilians could be evacuated from the location. The fortress was successfully stormed and the men of the garrison were massacred, while some women and children within were carried off as spoils of war.
725–726
The commander of the main Umayyad incursion in 725 was Mu'awiya ibn Hisham, who would go on to lead several subsequent sawa'if raids in the following years. However, his campaign in 725 made little progress, as it was met by scorched earth strategies employed by the Byzantines. They destroyed pastures in advance of the Umayyads, so that the Arabs would have difficulty sustaining the horses and beasts of burden of their army. Umayyad detachments retaliated by spreading out and burning abandoned villages and crop fields in their vicinity, but they inflicted limited damage, and were unable to make strategic headway on this occasion.
An invasion in late 725 brought better results for the Umayyads. Again commanded by Mu'awiya, the Arabs invaded with a large army, including a 4,000-strong detachment of recruits from Hijaz, as well as an elite unit named Waddahiyya. This expedition saw a number of settlements fall to the Arabs, and a column under the command of the veteran Maslama ibn Abd al-Malik even stormed and sacked Caesarea of the Anatolikon Theme on 13 January 726. Umayyad operations in these years were not limited to terrestrial offensives. By the year 726, possibly in response to the Byzantine attack on Egypt in 721, the Umayyads had bolstered the strength of their own navy. Consequently, an Umayyad fleet, under the command of the Jaziran Maymun ibn Mihran, was able to raid Byzantine possessions in Cyprus.
727
The Umayyad invasion of Asia Minor in 727 was an ambitious undertaking involving a massive army, and was again led by Mu'awiya ibn Hisham and Abdallah al-Battal. The total strength of the Umayyad force was recorded to be 100,000 strong, and was divided into two columns to engage different targets simultaneously: a vanguard of 15,000 men under al-Battal, and a main body of 85,000 men commanded by Mu'awiya. This incursion yielded initial success, as al-Battal conducted a lightning raid into Paphlagonia, where he took the city of Gangra by surprise and sacked it. Al-Battal then turned southwest and advanced towards the headquarters of the Opsikion Theme, Nicaea. The Umayyad vanguard caught the garrison of the city by surprise and blockaded the stronghold. However, al-Battal was not able to capture the settlement immediately, and thus settled for a blockade, while he awaited rendezvous with the main column under Mu'awiya. When Mu'awiya's main body rejoined with al-Battal's column, the unified Umayyad army subjected Nicaea to a full-scale siege. En route to Nicaea, Mu'awiya may have captured the fortress of Ateous (called Tabya in Arabic sources), though this victory appears to have been pyrrhic for the Umayyads, as their main army incurred severe casualties, which may have affected the outcome of the siege.
The two Umayyad commanders invested Nicaea for 40 days with assaults and siege engines, which eventually succeeded in breaching parts of the fortifications. However, the Umayyads could not successfully storm the stronghold despite these efforts. The siege was of such intensity that some of the Nicaeans fled the city across Lake İznik, but the presence of this lake also allowed soldiers and supplies to be sent by boat to reinforce the garrison of the city. Ultimately, the Umayyads were repulsed after sustaining heavy casualties, and broke off their siege at Nicaea. Following this campaign, the Umayyads diverted resources to the Transcaucasus, where Maslama faced mounting attacks by the Khazars.
728–729 Although the Byzantines had achieved a celebrated victory in their defence of Nicaea in 727, Mu'awiya's advances were only temporarily halted. The Umayyad attacks resumed in vigor the following year, with a punitive expedition led by Mu'awiya and Abdallah al-Battal, who advanced against the lands of the Armeniakon Theme in northeastern Asia Minor. The two commanders successfully captured the forts of Semaluos and al-Mawla. Naval operations also continued in 728, with either Abd Allah ibn Uqba al-Fihri or Abd al-Rahman ibn Mu'awiya ibn Hudayj al-Sakuni, conducting a seaborn expedition. The results of these ventures are unknown.
The sons of the caliph conducted a two-front pronged attack into Anatolia in 729, with Arab forces under Sa'id ibn Hisham entering Cappadocia again, while Mu'awiya campaigned in Eastern Anatolia. Sa'id marched as far as Caesarea, which had been captured by Maslama three years earlier. However, the Byzantines had used the time to refortify and restore the defences of the city, and as a result the garrison withstood the Umayyad invasion. Further east, Mu'awiya's expedition may have also faired poorly, though both al-Hisham brothers were able to reach the safety of Umayyad territory following their campaign. Another naval operation accompanied the terrestrial offensives in 729, under the leadership of Abdallah ibn Abi Maryam. The target and result of his attack is not recorded in surviving sources.
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