As a flourishing, much-envied city, throughout its more than thousand years of history, Byzantine Constantinople has often been the object of siege warfare. Depending on what one considers an actual siege to be like (are mere blockades or vain intentions to seize a city also sieges?), the immense stronghold at the Bosphorus may have been the purpose of up to twenty siege campaigns. Here, we will limit ourselves to the non-Muslim sieges of Byzantine Constantinople, thus excluding not only the most famous, Ottoman siege by Sultan Mehmed II and his troops in 1453, but also the two Arab sieges (674-678, 717-718) and the Byzantine retaking of the then Latin capital (since 1204) in 1261. The attempts by Bulgarian and so-called Nicaean forces (1235, 1260) to recapture the capital from the Latins will not be discussed either, while the siege(s) at the end of the Fourth Crusade are already treated in detail elsewhere in this encyclopedia. Among the remaining sieges are several Slavic (Bulgarian and Russian) attempts to seize the respectable and very influential city and a few efforts of some of Byzantium’s own military men during what could be regarded as Byzantine coups.

The first ‘tries’ worth to be mentioned are actually nothing more than repeated, though never-fulfilled plans, albeit by one of the most feared (and infamous) usurpers of Early Medieval history: Attila the Hun (r. 434-453). Already in the beginning of the fifth century, construction of Constantinople’s double Theodosian Walls (named after Emperor Theodosius II, r. 408-450; ca. 2 km to the west of the Wall of Constantine) had been intensified and brought to completion more quickly, exactly because of the threat of the Huns, who were marauding widely around the Danube and in the Balkans. In the early 440s, Attila for the first time seriously targeted the capital of what was then still the Eastern Roman Empire. Attila, at that moment ruling the Huns together with his brother Bleda, led very successful campaigns taking and plundering cities such as Singidunum (present-day Belgrade), Naissus (Niš), Serdica (Sofia), Philippopolis (Plovdiv) and Arcadiopolis (Lüleburgaz). However, the sight of the strongly fortified walls of Constantinople finally made the Huns hesitate, whereupon they turned northward. There they wiped out what remained of the Eastern Roman army that had been sent to stop them, thus forcing Emperor Theodosius II into a truce (the Treaty of Anatolius, 443, including large payments). Four years later, Attila, now ruling alone (Bleda died in 445, probably killed by his brother), for the second time marched into the Eastern Roman Empire. This time, the Huns were backed by contingents of subjected groups, including Goths and (the also Germanic) Gepids. Within the empire, trouble still increased due to a series of earthquakes in the first months of 447, causing thousands of victims in and around the capital and severely damaging its walls as well. To defend the city against Attila’s imminent invasion, the Theodosian Walls were not only restored – at record speed –, but even enlarged (inscriptions still commemorating this expansion). The Huns defeated the imperial army near the river Utus (the present-day Vit in northern Bulgaria), but this was no more than a Pyrrhic victory. The losses were too big to contemplate a serious attack on Constantinople’s (after all) too strong walls and Attila had to content himself with capturing some Balkan towns of minor importance, nonetheless reaching as far southward as Thermopylae. In 453, after the new Emperor, Marcian (r. 450-457) had refused to pay tribute, Attila is said to have armed his troops once again for a campaign towards Constantinople, although he now rather concentrated on the western boundaries of his Hunnic Empire. Anyhow, his wedding night – the Germanic girl Ildico being the last in a long row of brides – became fatal to Attila. The Scourge of God had probably drunk far too much and allegedly died of nosebleed, although it has recently been argued that it may have been Marcian who had a hand in Attila’s death. The Hunnic threat over Europe now soon disappeared.

1- The 9<sup>th</sup> century inscription of sea walls restored by Emperor Mikhael III’s uncle Bardas (Istanbul Archeology Museum)

The Huns, then, may not have physically disturbed the Constantinopolitan walls, but it was ‘thanks to’ their nearly unceasing menace that these walls were turned into one of the most complex and solid fortification systems man has ever built. Needless to say, this was of invaluable significance during the frequent attacks in the centuries to come. The first actual siege of Constantinople, the culmination of what is also known as the ‘last great war of Antiquity’, should be observed within the broad context of the internal (political) unrest at the end of the Justinian dynasty. The overthrow of Emperor Maurice (r. 582-602) by army officer Phocas (r. 602-610) provided a welcome pretext for Maurice’s ally, Chosroes II, the Sassanid king of Persia, to assault the Byzantine Empire. Chosroes and the Persians took the border town of Dara (in present-day city of Mardin, just north of Syria) and headed for Constantinople, right through Asia Minor. What was more, Chosroes claimed that Theodosius, the son of Maurice, was fighting on the Persian side. Although the son had actually been killed by Phocas’ men, a Byzantine commander-in-chief allowed this ‘Theodosius’ into the capital where he was even crowned. To blow up the difficulties even further for Phocas, he had to deal with a man named Heraclius, who came with his rebellious father from Byzantine Carthage and, after gathering many supporters, managed to take Constantinople in October 610 after a short blockade of the grain supply. After having Phocas executed, this Heraclius became the new emperor (r. 610-641), thus laying the foundation of a new century-long dynasty (named after himself). It was under this dynamic ruler that the city, in 626, experienced its first real siege from a conglomerate of foreign enemies: Chosroes’ Persians, a numerous host of Avars and far fewer Slavs. In the years before, Heraclius had been able to keep the Avars under control by offering them large subsidies, while the Persians – since the overthrow of Maurice more or less enduringly threatening the capital from the other side of the Bosphorus – had gained some important victories in the Asian part of the Byzantine Empire. They had sacked Jerusalem (614) and brought the Holy Cross to their capital Ctesiphon (in present-day Central Iraq). IWhile Heraclius was successfully campaigning in Persia’s northern and central territories in 626, they joined forces with the Avar troops and tried to besiege Constantinople from their positions in Chalcedon (Kadıköy). Patriarch Sergius is said to have very enthusiastically taken the lead of the defenders. All in all, they withstood the ten-day siege without difficulty. The city walls proved to be reliable and the boats of the enemies, which were provided by the Slavs, were no match for those of the Byzantine fleet. After this Byzantine victory – the praises of which were soon thereafter sung by George Pisides in his epic Bellum Avaricum – things went worse for Persia. It had to return Jerusalem and the Holy Cross (628), and by the end of the decade Byzantium had regained all the Asian territories it had lost since the turn of the century. A new formidable opponent in this vast area, however, was soon to appear. Already in 638, Jerusalem fell to the Arabs, Byzantium’s very first Muslim challenger, who vainly laid siege to Constantinople in 674-678 (under Emperor Constantine IV). During this first substantial defeat of the Arabs, the Byzantines introduced their mysterious ‘Greek fire’. In 717-718, a second Arab siege failed as well, but the victorious Emperor Leo III (the ‘Isaurian’) may have been influenced by the successes of the Arabs – who banned iconolatry – when in 726 he started what is now known as the first wave (until 787) of Byzantine iconoclasm.

The protagonist of the next siege, Khan Krum (r. ca. 800-814) of the Bulgarians (or ‘Bulgars/Bolgars’, as they are usually called until their conversion to Christianity in 865), is most famous for having made the skull of Byzantine Emperor Nicephorus (r. 802-811) into his ceremonial drinking goblet. Under Krum, the First Bulgarian Empire (681-1018) doubled in size, at the expense of Avar, but also of considerable Byzantine territory. What accounted for Krum’s raids southwards were likely to be Nicephorus’ atrocious behaviour (a.o. towards children) after seizing the then Bulgarian capital of Pliska in 811. The Bulgarians, however, had the Byzantine troops trapped, and Nicephorus killed, on their way back to Constantinople, whereupon intensive war operations were started (the ultimate goal of which turned out to be the Byzantine capital itself), especially since Emperor Michael I Rhangabe (r. 811-813) declined the peace treaty offered by Krum. The Bulgarians devastated and took many towns in Thrace and Macedonia and towards the summer of 813 found themselves camped near Adrianople (Edirne), from where they managed to set aside the Byzantine armies and headed for Constantinople, which they started to blockade. Having no fleet at their disposal, this was of course an impossible task. All this nonetheless cost Michael I his emperorship: he became a monk and was succeeded by Leo V (‘the Armenian’, r. 813-820), who immediately started negotiations with Krum. Emperor Leo invited Krum beyond the walls, but placed a couple of bowmen in ambush. The infuriated Krum, however, survived the plot and took revenge by ruining the land in front of the impregnable city and capturing Adrianople and Arcadiopolis, after which he allegedly prepared his troops for a renewed attack on the capital. But Krum’s death in 814 thwarted this plans, and a thirty-year period of peace between Bulgaria – under Krum’s son, Khan Omurtag – and Byzantium followed.

The following siege of Constantinople took place only eight years later: this time, under Emperor Michael II (‘the Amorian’, r. 820-829), it was (after Heraclius’ successful attempt in 610, see above) again a siege ‘from within’, that is to say, being part of an internal conflict. Historians still disagree about the nature of the rebellion (was it a social revolt or merely an attempt to seize political power?), and it is unclear as well whether the leader, known as Thomas the Slav, was really a Slav. The fact remains that he came from Asia Minor and soon gathered around himself a very diverse force of followers, including many poor and/or iconophile (Leo V had started the second – and last – wave of Byzantine iconoclasm, 815-843) inhabitants of the empire’s eastern parts. From 821 until 823, Thomas largely controlled Asia Minor and in this period he also attempted to capture Constantinople, an objective which was applauded by many Slavs who sided with Thomas as he was approaching the capital. At the end of 821, with an army of more than thirty thousand men and a considerable fleet, the rebel was able to harass Michael from three sides, deploying batteries of stone throwers in front of the walls. Superior artillery and some favourable winds, however, helped the defenders and winter forced Thomas to interrupt the siege. From the spring of 822 onwards, Thomas focused his attacks mainly on the Blachernae sector of the walls (i.e., on the northwestern parts), and although his fleet was nearly annihilated by the emperor’s navy, the rebellious troops still more or less kept on blockading the city. Finally, Michael had to lean upon his Bulgarian allies, on the basis of the above-mentioned peace treaty. Towards the end of the year, being threatened in the rear by Khan Omurtag and his troops, Thomas had to turn his army and led it into an open battle some hundred kilometres west of Constantinople (near present-day Marmara Ereğlisi). The result of this encounter with the Bulgarians remains uncertain, but it was clear that the capital was once again saved. Thomas the Slav chose Arcadiopolis as his ultimate city of refuge. He and the remainder of his men had to face a very effective blockade by Emperor Michael, who understandably showed no mercy at all when after several months Thomas was handed over by his totally exhausted last supporters.

2- Istanbul walls at the beginning of 20<sup>th</sup> century (Istanbul Metropolitan Municipality, Atatürk Library)

Under Michael II’s grandson, Emperor Michael III (r. 842-867), the so-called Rus for the first of two or possibly three times within a time-stretch of some eighty years proved to be a menace to the imperial city. The Rus (or in Greek Rhos) are generally associated with Kievan Rus, the Kiev-centred state which would ultimately give way to the expansion of Muscovy. In 860, however, Kiev had probably not been founded yet, and the Rus who suddenly appeared in front of the Constantinopolitan walls, should rather be connected with the Varangians: Norsemen who had started to assimilate with the Eastern Slavs around the large rivers in the west of present-day Russia. Historians think that the Rus were well-informed about Byzantium’s difficulties in the east of the empire. In the spring of 860, the Arabs had gained some alarming victories in Asia Minor and in the beginning of June, Emperor Michael left his capital to start a military campaign. Shortly thereafter, as if timed, some two or three hundred Rus dugouts (monoxyla) came sailing along the Bosphorus. The Rus heavily plundered the outskirts of Constantinople and murdered the inhabitants so brutally that the famous Patriarch Photius, from within the walls, publicly invoked the help of the Virgin Mary (Theotokos). Tradition has it that her intervention miraculously saved Constantinople, after more than fifty days of terror. Patriarch Photius’ sermons are our main source for the attacks of the Rus in these troublesome weeks, the later Russian sources being very confusing and giving the impression that they did not identify Byzantium’s ‘barbarous’ enemy with the Rus (and thus with their forefathers!). In any case, Photius does not give us a decisive answer to whether the ‘siege’ of the Rus was an active attempt to capture the city or merely a (systematic) military raid around its shores. Besides, the city was indeed saved, miraculously or not, but it is far from sure whether the Rus were actually overpowered: (more) probably, they just returned to the Black Sea and beyond after having collected enough booty. Two years later, Emperor Michael started organizing the Christianization of the Slavs: the mid-860s are the period of the mission of (the later Saints) Cyril and Methodius. After having created the Slavic alphabet, these so-called Apostles of the Slavs brought it, together with Christianity, to Moravia. Later that decade, also the Bulgarians were converted (see above). The Rus, however, had to wait until 988 before their ruler (and later Saint) Vladimir made Rus(sia) once and for all accept Christianity.

3- Istanbul walls (Ayvansaray)

Before this key moment, we know yet of other Rus incursions into the Bosphorus, the first one of which, in 907, is problematic as regards its date (according to some: 904) and even its historicity. The Tale of Bygone Years, a famous Russian chronicle, ascribes a campaign around, rather than against the walls of Constantinople, to Oleg of Novgorod and his Rus fleet. Byzantine Greek sources, for their part, do not mention this encounter, which made some scholars think that the Russian chronicle in fact speaks about the attacks of 860 (see above). Indisputably, however, in 907 a peace treaty has been secured between Byzantium and Rus to the benefit of the latter. This may of course point to a military clash immediately before, but in any case: it is unlikely that this was of any real threat for the walls of Constantinople. Be that as it may, in 941, the Rus, under Oleg’s successor, Igor of Kiev, without doubt were witnessed raiding into the Bosphorus. Again, the Byzantine army was involved in a conflict with the Arabs, this time in the Mediterranean, and, once more, the Rus’ timing suggests that they were well aware of this. Emperor Romanus I Lecapenus (r. 919-944) sent his successful general John Curcuas to the capital, where he met few problems defeating the Rus. Their fleet, already fleeing, was fatally reduced by means of ‘Greek fire’, which once more turned out to be a very reliable Byzantine naval weapon. It is obscure, again, to what extent this encounter was an actual siege, but in contrast with the previous raids it was crystal clear now that the Byzantines had won. Byzantium, and especially the splendid capital with its awe-inspiring Holy Sophia Cathedral kept on exerting an extreme attraction on the Rus(sians), even until this day. The already-mentioned Tale of Bygone Years includes a much-cited legend in which Vladimir (see above) precisely chooses Eastern Christianity for his fellow citizens because of the thrilling and heavenly beauty, which his envoys had perceived in Constantinople. So it came as no surprise that Rus and Russia covered their vast lands with churches in the Byzantine style, in time of course providing them with their own architectural characteristics. In the decennia after the Christianization of the Rus (988), they undertook two other minor naval raids past or in the direction of Constantinople, but it was not until Ottoman times that Russia would again lay (ideological) claim to the city.

The dates of the last siege to be discussed here are exactly known: during four days in the autumn (25-28 Sept.) of 1047, the capital had to be defended against the troops of the Byzantine general Leo Tornicius. Being a nephew of Emperor Constantine IX Monomach (r. 1042-1055), Tornicius was a much nobler rebel than Thomas the Slav, who two centuries earlier (see above) had also tried to seize Constantinople ‘from within (the empire)’. Having gathered a considerable amount of supporters and several higher-ranked military men from the western provinces, Tornicius, from his nearby birthplace, Adrianople, marched towards the sturdy city walls, where the assailants almost instantly repulsed a break-out from a quickly improvised army unit. Tornicius allegedly just waited a little too long now to take advantage of the panic that suddenly spread all over the city. The first night allowed Emperor Constantine to re-establish order and to await help from extra forces. His momentum gone, in the next three days Tornicius did not manage to form a serious threat to the defenders, while Emperor Constantine is said to have acted as a real hero. Having fled and entrenching himself in a church some two hundred kilometres west of the capital (in Bulgarophygon, present-day Babaeski), Tornicius was soon arrested and blinded, a typical Byzantine method of punishment, rendering the victim unfit for the throne.

New enemies, however, were soon to appear. The eleventh century still saw the swift approach of the Seljukid Turks from the East, while in the West, the Great Schism (1054) gave a theological boost to the increasing political and economic conflicts between Eastern and Western Christianity. Already in 1097, the Crusaders – on their way to Jerusalem – are said to have had the intention to attack Constantinople, and this was indeed realized little more than a century later, as the fateful apogee of the Fourth Crusade (1202-1204), discussed elsewhere in this encyclopedia. The proud walls, highly respected churches and other magnificent buildings of Constantinople indeed fell for the first time into foreign hands… and these were Christian. ‘Latin Constantinople’ was granted only a short life, and was soon recaptured under the lead of general Alexius Strategopulus (1261). Neither the Byzantine Empire nor its capital, however, ever fully recovered from the many blows in this turbulent century, and when Constantinople on 29 May 1453 was finally taken by Sultan Mehmed II, the impressive city at the Bosphorus was almost an island in an Ottoman sea.


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This article was originally written in English for History of Istanbul and its Turkish translation was published in 2015.