Maslama ibn Abd al - Malik Maslama ibn Abd al - Malik ( , in Greek sources , " Masalmas " ; ) was an Umayyad prince and one of the most prominent Arab generals of the early decades of the 8th century , leading several campaigns against the Byzantine Empire and the Khazar Khaganate . He achieved great fame especially for leading the second and last Arab siege of the Byzantine capital Constantinople , and for strengthening the Muslim presence in the Caucasus , among other things as the " founder of Islamic Derbent " . Early life and career . Maslama was the son of the Umayyad caliph Abd al - Malik ibn Marwan ( reign ed 685 – 705 ) and half - brother of the caliphs al - Walid I ( r . 705 – 715 ) , Sulayman ( r . 715 – 717 ) , Yazid II ( r . 720 – 724 ) and Hisham ( r . 724 – 743 ) . Maslama himself was excluded from the line of succession as his mother was a slave . He is first mentioned as leading , along with his nephew al - ' Abbas ibn al - Walid , the annual summer campaign ( " ṣawā ' if " ) against the Byzantine Empire in 705 . His first major expedition was the 707 – 708 campaign against the Byzantine city of Tyana in southeastern Asia Minor , which was launched in retaliation for the defeat and death of the distinguished general Maimun the Mardaite the year before . The siege lasted through winter and the Arab army faced great hardship , but after the Arabs defeated a Byzantine relief force in spring 708 , the city surrendered . A few months later , in the summer , Maslama led another expedition into Asia Minor and defeated a Byzantine army near Amorium , while in 709 he raided into the region of Isauria . In the same year , Maslama was appointed military governor of Armenia and Azerbaijan , succeeding his uncle Muhammad ibn Marwan . He had already held the post of governor of Jund Qinnasrin , which was based around Aleppo . His governorship of this province was not as well - documented by early Arabic chroniclers as his other posts , although contemporary historian Jere L . Bacharach claims Maslama was the likely patron of the Umayyad Mosque of Aleppo and possibly some construction works in Qinnasrin . Together , command of these provinces effectively gave him complete control of the Caliphate ' s entire northwestern border . From this position he launched several campaigns against the Byzantines , devastating Galatia and sacking Amaseia in 712 , and taking Melitene in 714 . He was also the first to establish the Caliphate ' s presence north of the Caucasus , leading to the commencement of direct conflict with the Khazars ( the Second Arab – Khazar War ) . In 710 and again in 714 , he marched his army up to Bab al - Abwab ( " Gate of Gates " , the Arabic name of Derbent ) , which he took and destroyed during the latter expedition . Siege of Constantinople . From 715 Maslama was the leading general in the plans of his brother , Caliph Sulayman , to conquer the Byzantine capital , Constantinople , as Sulayman himself was too ill to lead the campaign in person . Maslama led a huge army , which sources report to have numbered 120 , 000 men and 1 , 800 ships . In late 715 , the Arab vanguard crossed the Taurus Mountains into Byzantine territory , Maslama following in spring 716 with the main army and the fleet . The Arabs ' plans were aided by the recurrence of civil strife , which had plagued the Byzantines since 695 ; Emperor Anastasius II was overthrown by Theodosius III in 715 , who was in turn opposed by the " strategos " of the Anatolic Theme , Leo the Isaurian . Maslama hoped to use the divisions among the Byzantines for his own benefit and initiated contacts with Leo , but the latter used the negotiations to outwit the Arab general and occupied for himself the strategic city of Amorium , which Maslama had intended to use as his winter base . As a result , Maslama marched further west , to the coastlands of the Thracesian Theme . There he spent the winter , while Leo marched onto Constantinople , which he entered in March 717 . In early summer 717 , Maslama with his army crossed from Asia into Europe over the Dardanelles , and proceeded to besiege Constantinople from land and sea . His navy , however , was soon neutralized by the use of Greek fire , and as his army was unable to overcome the city ' s land defences , the siege continued into the winter , which was especially severe that year , with snow covering the ground for three months . Maslama had brought along many supplies , but they either soon ran out or were lost — Arab accounts make much of Leo tricking the Arab general yet again during negotiations into handing over or destroying a significant part of his hoarded supplies — and the army began to suffer from hunger and disease . In spring , reinforcements arrived in the shape of two large fleets from Egypt and Ifriqiya , but a large part of their crews , who were mostly conscripted Christians , went over to the Byzantines , and Leo ' s navy managed to destroy or capture the Arab fleets . The Byzantines also defeated an Arab army marching to aid the besiegers through Asia Minor , while Maslama ' s men had to contend with attacks by the Bulgars as well , which cost them many men . The siege had clearly failed , and the new Caliph , Umar II ( r . 717 – 720 ) , ordered Maslama to retreat . On 15 August 718 , after thirteen months of siege , the Arabs departed . Despite its failure , Maslama ' s attempt to capture Constantinople became celebrated in later Muslim literature , with several surviving accounts , mostly semi - fictional , in which the historical defeat was transformed into a sort of victory : Maslama was said to have departed only after symbolically entering the Byzantine capital on his horse accompanied by thirty riders ; Leo received him with honour and led him to the Hagia Sophia , where the emperor paid homage to the Arab general . The tales of the siege influenced similar episodes in Arabic epic literature , where Maslama appears associated with another legendary Arab hero of the wars against Byzantium , Abdallah al - Battal . Furthermore , Byzantine tradition , as recorded in the 10th - century " De Administrando Imperio " , held that during the siege Maslama convinced the Byzantines to build Constantinople ' s first mosque , near the city ' s " praetorium " . Later Ottoman tradition also ascribed the building of the Arap Mosque ( located outside Constantinople proper in Galata ) to Maslama , although it erroneously dated this to around 686 , probably confusing Maslama ' s attack with the first Arab siege in the 670s . In reality , the mosque near the " praetorium " was most likely erected in about 860 , as a result of an Arab embassy in that year . Governorship in Iraq and the Caucasus . After his failure at Constantinople , Maslama was dispatched to Iraq to quell the Kharijites . Following Umar ' s death and the accession of his brother Yazid II in 720 , he was tasked with the suppression of the revolt of Yazid ibn al - Muhallab , whom he defeated and killed in August 720 . He nevertheless fell out of favour with the Caliph , who resented and feared his power as governor of both Iraqs , as well as his interfering in the succession : Maslama favoured his brother Hisham over Yazid ' s son Walid . Yazid soon recalled Maslama from his post , ostensibly because he had failed to deliver his provinces ' tax haul to Damascus , and replaced him by his protege , Umar ibn Hubayra . Maslama then disappears from the sources and re - emerges in 725 , shortly after Yazid ' s death and the accession of Hisham , who sent Maslama to replace al - Djarrah ibn Abdallah al - Hakami in the Caucasus front against the Khazars . Initially , however , Maslama was mostly active in the Byzantine front , and the war against the Khazars was delegated to al - Harith ibn Amr al - Ta ' i . In winter 725 , Maslama led an expedition against Asia Minor from Melitene , which culminated in the sack of Caesarea on 13 January 726 . Along with the capture of Gangra by Abdallah al - Battal in 727 , this was one of the major successes of Arab arms against the Byzantines in the 720s . A few months later , he also led the otherwise unremarkable northern summer expedition into Byzantine territory . In 727 – 728 , his attention was diverted by Khazar attacks which reached deep into Azerbaijan . Although Maslama was able to drive them back and recover control of the Darial Pass , his 728 campaign across the Caucasus was difficult , bloody and indecisive . Maslama ' s troops were reportedly engaged in up to thirty or forty days of constant fighting in miserable weather , and although he claimed victory in a battle over the Khazar " khagan " himself , the expedition did not achieve any results , and came close to being defeated . Certainly it did little to stop Khazar attacks south of the Caucasus , which resumed in 729 . Maslama was removed from office in the same year , and replaced by al - Djarrah . He is then recorded by the Byzantine chronicler Theophanes the Confessor as having been responsible for the sack of the fortress of Charsianon in late 730 , but Arab sources credit Mu ' awiya ibn Hisham for this act . In the Caucasus , the situation quickly deteriorated after Maslama ' s departure . While al - Djarrah campaigned north of the Caucasus , the Khazars swung behind him and attacked his main base , Ardabil . Hastening to relieve the city , al - Djarrah was defeated and killed , and his army practically annihilated in a battle outside the city on 9 December 730 . Faced with this crisis , the Caliph appointed Maslama as the new governor of Armenia and Azerbaijan but , in the meantime , the veteran general Sa ' id ibn Amr al - Harashi managed to recover the situation and defeat the Khazar army . Maslama , allegedly out of jealousy for Sa ' id ' s successes , had Sa ' id imprisoned until Hisham ordered his release . Throughout 730 and 731 Maslama , with a large army at his disposal , cleared the provinces south of the Caucasus of the Khazars , and then advanced beyond the mountains , sacking a couple of settlements and defeating the " khagan " in pitched battle . He also recovered the strategic fortress of Bab al - Abwab from the Khazars who had occupied it by poisoning its water supply , and reorganized it as a military colony ( " misr " ) , resettling it with 24 , 000 soldiers . His tenure however was evidently judged as not successful enough , and he was replaced on 3 March 732 by Marwan ibn Muhammad . Maslama thereafter retired from public life , possibly to his extensive estates in northern Syria . He died on 24 December 738 .