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Dedicated to the military history and civilization of the Eastern Roman Empire (330 to 1453)


"Time in its irresistible and ceaseless flow carries along on its flood all created things and drowns them in the depths of obscurity."

- - - - Princess Anna Comnena (1083–1153) - Byzantine historian

Wednesday, February 5, 2014

The Siege of Sirmium and The Invasion of the Avars


Left to right - Slavic peasant, Avar warrior and Avar nobleman approx. 7th century AD.

The Invasion of the Eurasian Avars


The Roman Empire faced a thousand years plus of endless waves militaristic barbarian invasions including Huns, various Gothic tribes, Arabs, Bulgars and Turks.  The 6th century saw the newest barbarian tribe to threaten the Empire - the Avars.

The Avars were a group of equestrian warrior nomads who established an empire spanning considerable areas of Central and Eastern Europe from the late 6th to the early 9th century. They were ruled by a Khagan, who led a tight-knit entourage of professional nomad warriors.

In 557, the Avars sent an embassy to Constantinople, marking their first contact with the Eastern Roman Empire, presumably from the northern Caucasus. In exchange for gold, they agreed to subjugate the "unruly gentes" on behalf of the Byzantines. They conquered and incorporated various nomadic tribes -- Kutrigur Bulgars, Onogur/Utigur Bulgars, and Sabirs—and defeated the Antes.

By 562 they controlled the steppes north of the Black Sea and the lower Danube basin. By the time they arrived in the Balkans, the Avars formed a heterogeneous group of about 20,000 horsemen. After the Byzantine Emperor Justinian I (reigned 527-565) bought them off, they pushed northwest into Germania. However, Frankish opposition halted further expansion in that direction.
Roman Emperor Maurice
Flavius Mauricius Tiberius Augustus
Maurice stabilized the Roman frontier
in the Balkans.
By Emilian Stankev (from ‘Rulers of the
Byzantine Empire’ published by KIBEA)

Seeking rich pastoral lands, the Avars initially demanded land south of the Danube River (in present-day Bulgaria), but the Byzantines refused, using their contacts with the Göktürks as a threat against Avar aggression. They thus turned their attention to the Carpathian plain and to the natural defenses it afforded.

By about 580 the Avar Khagan, Bayan, established supremacy over majority Slavic, Hunno-Bulgar, and Germanic tribes. When the Eastern Roman Empire was unable to pay subsidies or hire Avar mercenaries, the Avars raided their Balkan territories.

According to Menander, Bayan commanded an army of 10,000 Kutrigur Bulgars and sacked Dalmatia in 568, effectively cutting the Byzantine land link with North Italy and the West.

At Maurice's accession, the greatest omissions of his predecessors were to be found in the Balkans. Justinian I neglected Balkan defenses against the Slavs, who threatened the frontier since 500 and pillaged the Balkan provinces ever since.

Although he rebuilt the fortifications of the Danube Limes, he abandoned campaigns against the Slavs in favour of a policy focusing on western and oriental theatres.

His nephew and successor Justin II played off the Avars against the Gepids and later on against the Slavs. But this only allowed the Avar Khaganate to become a more powerful threat than Gepids and Slavs. As Justin II let the Avars attack the Slavs from Roman territory, they soon noted where the most booty was to be made.

To make matters worse, Justin II started the Roman-Persian War of 572–591, which tied down forces in the east at a time when they were needed in the Balkans. Maurice's predecessor and father-in-law Tiberius II Constantine emptied the treasury. For all those reasons, the Slavic incursions in the Balkans continued.

A few months before Maurice's accession in the winter of 581/2 the Avar Khagan Bayan, aided by Slavic auxiliary troops, took Sirmium, a large fortified settlement south of the Danube. Doing this, Bayan established a new base of operations within Roman territory from which he could raid the anywhere in the Balkans unhindered.

The Avars were only compelled to leave territory once the Romans under Maurice agreed to pay 80,000 solidi annually. The Slavs, partially under Avar rule, were not bound by the treaty and continued to pillage south of the Danube, making the Avars and Slavs quite different threats.



An Avar Invasion
Originally from the Pontic-Caspian steppe, the Avars were a group of equestrian warrior nomads who established an empire spanning considerable areas of Central and Eastern Europe from the late 6th to the early 9th century.


Roman Wars on Four Fronts
Romans faced wars on multiple fronts in the Balkans,
Italy, North Africa and against the Persian Empire.


So many historians fail to understand the unbelievable military and economic pressure the Eastern Roman Empire was under from constant invasions.

Simply, the barbarian invasions never ended.  They just kept coming over and over.  The massive military expense of wars drained the Empire dry.  Virtually all available funds were spent just to survive leaving little for building projects.

A major consideration is what I call the "de-Latinization" of the Empire.  With every barbarian thrust over the border you saw the destruction of Roman peoples, towns, cities, infrastructure and the economy.  Lands lost to the Empire meant a loss of taxes paid to Constantinople as well as recruiting grounds for soldiers to defend the state.

Every day was a nightmare.  -  Historians tend to write about a single Eastern Roman battle with no thought given to an Empire wide view. 
While the  Eurasian Avars were invading the
Balkans the Romans fought an invasion of
Italy by the Germanic Lombard tribe. 

The Eastern Emperors and their generals in Constantinople woke up every day to a living nightmare of horror.  The Empire was monstrously huge with multiple wars both large and small often happening simultaneously on several continents.  If the Emperor transferred troops from one front to strengthen another he would only invite invasion on the first front.

The Avars were only one of many problems.

Tiberius II Constantine negotiated a truce with the Avars, paying them 80,000 nomismata per year, for which the Avars agreed to defend the Danube frontier, thereby allowing Tiberius to transfer troops across to the east for a planned renewal of the conflict against the Persians.

In 575 Tiberius began moving the armies of Thrace and Illyricum to the eastern provinces. Buying time to make the necessary preparations, he agreed to a three-year truce with the Persians, paying 30,000 nomismata, though the truce excluded action in the region around Armenia.

Not content with making preparations, Tiberius also used this period to send reinforcements to Italy under the command of Baduarius with orders to stem the Lombard invasion. He saved Rome from the Lombards and allied the Empire with Childebert II, the King of the Franks, in order to defeat them. Unfortunately, Baduarius was defeated and killed in 576, allowing even more imperial territory in Italy to slip away.

Tiberius was unable to respond as the Persian Sassanid Emperor Khosrau I struck at the Empire’s Armenian provinces in 576, sacking Melitene and Sebastea. Shifting his attention eastward, Tiberius sent his general Justinian with the eastern armies to push the Persians back across the Euphrates. The Byzantines followed, and pushed deep into Persian territory, culminating in a raid on Atropatene.

In 577, however, Justinian was defeated in Persian Armenia, forcing a Byzantine withdrawal.  In response to this defeat, Tiberius replaced Justinian with the future Emperor Maurice. During the truce which Tiberius concluded with Khosrau, he busily enhanced the army of the east, not only with transfers from his western armies but also through barbarian recruits, which he formed into a new Foederati unit, amounting to some 15,000 troops by the end of his reign.


Roman – Persian War of 572–591
The Roman armies faced a major war with the Persian Empire in the east.  At the same time they face invasion in the Balkans by the Avars, the invasion of Italy by the Lombards and a North African war against the Berbers. 

Solidus of Emperor Tiberius II Constantine wearing consular robes.


Throughout 577 and into 578, Tiberius avoided all other entanglements which would have distracted him from the approaching Persian conflict. He appeased, quite successfully, both Chalcedonian and Monophysite Christians by the use of strategic appointments and the easing of persecutions. He paid the Lombard tribal chieftains some 200,000 nomismata in an attempt to keep them divided and prevent the election of a king.

When the Slavs invaded Illyricum, he transported Avar armies to attack them and force their retreat. Consequently, when Khosrau invaded Roman Mesopotamia in 578, his general Maurice was able to invade Persian Arzanene and Mesopotamia, sacking a number of key towns and forcing the Persians to abandon their advance and defend their own territory. It was during this period that the ailing Emperor Justin finally died in early October 578.

The ongoing success against the Persians in the east once again allowed Tiberius to turn his gaze westward. In 579 he again extended his military activities into the remnants of the Western Roman Empire – he sent money and troops to Italy to reinforce Ravenna and to retake the port of Classis. He formed an alliance with one of the Visigothic princes in Spain who was fomenting rebellion, and his generals defeated the Berbers in North Africa.

The reality, however, was that the Empire was seriously overextended. In 579, with Tiberius occupied elsewhere, the Avars decided to take advantage of the lack of troops in the Balkans by besieging Sirmium.

At the same time, the Slavs began to migrate into Thrace, Macedonia and Greece, which Tiberius was unable to halt as the Persians refused to agree to a peace in the east, which remained the Emperor’s main priority. To top it all off, the Army of the East was beginning to become restless, as they hadn’t been paid, to the point where they threatened to mutiny.

In 580, the general Maurice launched a new offensive, raiding well beyond the Tigris. The following year (581), he again invaded Persian Armenia, and succeeded in almost reaching the Persian capital at Ctesiphon before a Persian counter-invasion of Byzantine Mesopotamia forced him to retreat back to deal with this threat.

By 582, with no apparent end to the Persian war in sight, Tiberius was forced to come to terms with the Avars, to whom he agreed to pay an indemnity and to hand over the vital city of Sirmium, which the Avars then destroyed. Unfortunately, the migration of the Slavs continued, with their incursions reaching as far south as Athens.

Although a new Persian invasion was halted with a significant defeat at Constantina in June 582, by this stage Tiberius was dying, apparently having eaten some poorly prepared, or possibly deliberately poisoned, food.

The City of Sirmium
Protected on two sides by the Sava River, Sirmium would have presented major
problems to any attacking army.
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In the 1st century AD, Sirmium gained a status of a colony of the citizens of Rome, and became
an important military and strategic center of Pannonia province. The war expeditions of
Roman Emperors Trajan, Marcus Aurelius, and Claudius II were prepared in Sirmium.
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The only known unexcavated Roman Hippodrome in the world is in Sirmium. A colossal
building about 150m wide and 450m long lies directly under the Sremska Mitrovica town
center and just beside the old Sirmium Emperor's Palace (one of just a few Sirmium publicly
accessible archeological sites). The presence of the arena has clearly affected
the layout of the present town.
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Ammianus Marcellinus called Sirmium "the glorious mother of cities".






































The Attacks on Sirmium (568–582 AD)


The Siege of Sirmium in 580–582 was a decisive event in the history of the Balkans.

The endless invasions by Eurasian barbarian tribes resulted in a steady "de-Latinization" of the Roman Balkan provinces.

For centuries Sirmium had served as a major civilian and military capital for the Roman Empire.  The fall of the city to the Avars deprived the Romans of its major stronghold on the northwestern Danube, opening the path for devastating incursions by the Avars and their Slavic allies into the Balkans.

Sirmium, which for much of the 6th century had been controlled by the Goths and then the Gepids, had come back under Roman control in 567. The Avars appeared along the Danube at about the same time.

The Avars launched a first attack on Sirmium in 568, but were seen off by the local governor, Bonus.

Bonus resurfaces in chronicles about 568-570 as a general. His exact position in the military hierarchy is uncertain, but the location of his activities at Sirmium, while still being in charge of the Danube limes, suggests the position of a magister militum  per Illyricum.

The spring of 568 found the Avars besieging Gepid controlled Sirmium.  Avar khagan Bayan's ultimate objective was Sirmium; at the original negotiations, he already requested that Langobards provide guides who could lead him against Sirmium.

Avar Nobleman

Moving in through the Moravian Pass and along the left bank of the Danube, 'taking immense pains and covering a long distance,' he set upon the Gepids. The late Langobard chronicles naturally attribute to their own king and people the glory of defeating the Gepids. But Byzantine contemporaries, who were well-informed and had a direct interest in the matter, recorded that it was Bayan who had 'defeated them in war' and 'smashed the Gepids' state'.

Bayan defeated the Gepids' main force, led by King Kunimund; the latter was killed in battle, and Bayan, in keeping with ancient Eastern custom, had his opponent's skull turned into a drinking bowl before presenting it — ostensibly in friendship — to Alboin.

Thereupon, Bayan immediately crossed the Danube to attack Sirmium's Gepidic defenders. The commander of the latter, Usdibad, did not wait for the Avars to arrive; he and his soldiers surrendered to the East Roman forces, who were on a state of alert. The Gepids' heir apparent, Reptila, fled to Constantinople, as did the head of the Gepid Arian Church, Bishop Thrasarik.

By the time Bayan reached Sirmium, the town was already defended by Bonos's Byzantine troops; the latter repulsed the Avar cavalry, which was unprepared for the siege of a fortress.

Bonus was in charge of the defense within the walls and was wounded in combat. When negotiations started between the defenders and the besiegers, Bonus was initially unable to attend the meetings. The Avars started suspecting that their opponent was dead, forcing Bonus to appear to them in person. The Avars eventually agreed to lift the siege in exchange for a "gift" (payment). Bonus sought the approval from Emperor Justin II.

Months later, Bonus allowed an Avar embassy to cross Byzantine areas towards Constantinople. The negotiations at the capital failed. Justin II reprimanded Bonus for granting protection to an embassy that had clearly unacceptable demands. His message to Bonus also warned the general to prepare for renewed hostilities. In 569/570, Tiberius II Constantine, the comes excubitorum, instructed Bonus to guard the river crossings of the Danube once more. His subsequent activities are unknown.

The 10th-century Suda lexicon preserves another fragment of Menander Protector concerning Bonus, though its context is left unclear. The passage has Bonus warning his men that the Avars use battle cries and the beating of the drums to unnerve their enemies. He instructs his forces to answer with battle cries of their own. 

The "Suda On Line" project translates the relevant passage (E, 2310): "The Avars in their battle-charge wanted to raise a confused and fierce noise, and along with their yelling to make a thud on their drums, so that the din would be raised so much that it would astonish and terrify the Roman army. Since Bonos knew this in advance, he forewarned the soldiers, so that they would not be dumbfounded by the melee, but imitating in advance what was going to happen, to be accustomed to what was to come by the similarity even before the event, and when they perceived the beating of the drums, they themselves would beat in return with their shields and shout the war-song and sing a paean and make a thump on the water-pots (which were made of wood)."

The Byzantines secured peace with the Avars through the payment of an annual tribute, which by 578 had risen to some 80,000 solidi.

Eastern Roman Soldiers

The Second Attack on Sirmium (580 - 582 AD)

In 580 began the second attack on Sirmium.  The problem is this is yet another major Byzantine military campaign with nearly zero historical information available.  Even Edward Gibbon's massive "The Decline and Fall of the Roman Empire" spends only a few sentences on the subject with no meaningful detail.

We need to fill in the huge historical gaps using logic and our knowledge of other campaigns.

Was the city of Sirmium Important?  -  The actions of both the Romans and the Avars prove the city was very important.  In two campaigns the Avars targeted the city first for conquest.  The second campaign lasted nearly three years indicating a political and military will to make the capture of the city a priority as a key to the future conquest of the Balkans.

For the Romans, Sirmium had been an important regional and Imperial capital for centuries.  An Imperial Palace complex had been built there and a Hippodrome constructed for public entertainment.  The importance of the city is indicated that the Roman commander refused to surrender the city to the enemy for nearly three years until instructed to do so by the Emperor.
Roman Urban Militia
Modern reconstruction of 6th century urban
militiaman.  His blue tunic marks him as
a member of the “Blues Circus Fraction”.
The double head eagle though appeared
after the 14th century.
Thanks to Koryvantes

Certainly the Avars felt they had to take the city before trying to advance deeper into the Balkans.  The Avars could not move south with a major Roman garrison intact in their rear.

What Forces Were Involved?  -  There are no records of the numbers of troops involved.  We do know that the Emperor shipped regiments from the Balkans to the eastern front to fight in the Persian War.   Historians claim the city did not have enough provisions or an "effective" garrison . . . whatever that might mean. 

But the truth of the events has the city garrison, perhaps with the help of a drafted militia,  standing against the Avars for nearly three years.  So there were enough soldiers at hand to man the walls and protect the city.

The Avars would have needed a significantly larger force than the Romans in order to maintain a siege.  I suspect their force would fluctuate over the months and years, but at least several thousand would be on hand to keep the Romans trapped inside.

Was The City Reinforced?  -  We know at the beginning of the siege that the Emperor ordered officers from Illyria and Dalmatia to the city to help organize the defenses.  I suspect the officers did not travel alone so they may have brought a small party of soldiers with them.  It is very possible that over the years that the garrison received periodic small amounts of supplies and reinforcements from neighboring Roman towns.

The Avars may have controlled the countryside with their cavalry, but they faced the task of keeping thousands of their troops supplied with food for years.

What Fighting Took Place?  -  Unfortunately there are no records of battles with the Avars, but I am almost 100% sure that the opposing forces did not sit and stare at each other doing nothing for nearly three years.

The Avars were equestrian warrior nomads who appeared to have no ability or interest in constructing siege weapons to bring down the city walls.  A siege causing starvation is the best they could manage. 

The Avar Khagan would have faced rebellion in his ranks from restless soldiers with nothing to do for months on end.  The Khagan initially would have tried attacks on the city testing the defenses.  As the Romans held firm the Khagan would probably have planned a regular series of smaller day and night probes of the city walls hoping to catch the Romans off guard.

Being short on troops the Roman garrison may not have responded to the Avar attacks beyond cheering from the walls at the defeat of the enemy.  If neighboring Roman garrisons had tried to help resupply Sirmium by river or land at night there could have been a number of small actions against the Avars.

The Nearby Roman Fortress of Singidunum.

What We Do Know  -  Historian Edward Gibbon says the Avar Khagan Bayan I marched with his men to the Roman Fortress of Singidunum which controlled the conflux of the Danube and Sava Rivers.  An Avar fleet of large boats had been constructed to transport bridge making materials up the rivers. 

The Roman commander of this strong garrison challenged the Khagan as to his intentions saying his movements were a violation of the peace treaty.  The Khagan swore oaths that he was not hostile to the Empire saying, "If I violate my oath may I myself, and the last of my nation, perish by the sword."  The Khagan claimed he was simply moving to attack Slav invaders who had refused to pay the Avars their annual tribute.

The Bishop of Singidunum held services with the rather disrespectful Avars who gave even more oaths of friendship.

The Avar Khagan marched with his men from Singidunum following the right bank of the Sava River to Sirmium.

Once the city was besieged Bayan said, "Inform the Emperor that Sirmium is invested on every side.  Advise his prudence to withdraw the citizens and their effects, and to resign a city which it is now impossible to relieve or defend."
Byzantine Infantry 6th C. AD

The city at the time lacked a large enough garrison and unprepared to withstand a siege, as most of the Byzantine forces were engaged in the east against Sassanid Persia.  The Byzantine Emperor Tiberius II tried to forestall the Avar attack by diplomatic means, but when the Khagan′s ambassador demanded the surrender of the city Tiberius said in reply, "I would sooner give your master one of my two daughters to wife than I would of my own free will surrender Sirmium."

An interesting side note.  The Avar ambassador was returning from Constantinople with his Roman escort when the entire party was killed by Slav pillagers.  This casually mentioned event in Byzantine accounts tells us a great deal about the lawless conditions in the open countryside of the Roman Balkan provinces.

Tiberius's armies were committed in Persia and Italy, but managed to send in a few officers from Dalmatia and Illyria to oversee the city's defenses.  The Roman commander Theognis met with the Khagan on the islands of Casia and Carbonaria, but the negotiations proved to be fruitless.

Despite the relative weakness of the garrison, the city resisted for almost three years.  With no end in sight for the Persian War in late 581 or early 582, shortly before his death, that Tiberius agreed to surrender the city in exchange for the lives of its citizens. The Avars spared the population, but took their possessions and 240,000 solidi from the Emperor, as arrears of the tribute owed over three years.

Aftermath

The Slavs took advantage of the siege of Sirmium to raid deeply into Roman territory.  The Slavs began to raid further south into Macedonia and Greece, evidenced by many coin hoards in the region, particularly in Attica near Athens and in the Peloponnese.

With Sirmium taken Bayan established a new base of operations within Roman territory from which he could raid the anywhere in the Balkans unhindered.

The new Emperor Maurice's forces were tied down for years in a war against the Persians.  He could muster only a small army against the Avars and Slavs in the Balkans.

In a long campaign lasting until 602 Maurice pacified the Balkan borders, a feat not performed since the reign of Anastasius I. Avars and Slavs had been kept sternly at bay. The provinces were at a stage of potential recovery; reconstruction and resettlement were the keys to firmly secure Roman rule again. Maurice had plans to settle Armenian militia peasants within the depopulated areas and to Romanize the Slavs settlers in the area.


Golden Roman helmet found near Sirmium; it has been
exhibited in the Museum of Vojvodina in Novi Sad.

Imperial Palace Complex
  Only part of the Imperial Palace Complex at Sirmium can be seen. The walls and pavements preserved there represent for the most part the residential quarters of the palace. Evidence of the luxurious interior decoration is provided by the fragments of frescoes, mosaic pavements and architectural ornament in various kinds of stone, which were imported from different parts of the Roman Empire – Egypt, Asia Minor, Greece, Italy.
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Installations for a radiant heating system were uncovered beneath almost every floor in the Sirmium Imperial Palace. The long duration and frequent use of the Imperial Palace are documented by the numerous structural repairs, mosaic pavements in several levels and the large quantity of archaeological artifacts recovered.

Ruins of Imperial Palace at Sirmium


Northern Balkans in the 6th century.
Click on map to enlarge.


Sirmium, Capital of the Praetorian Prefecture of Illyricum
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In 293, with the establishment of tetrarchy, the Roman Empire was split into four parts; Sirmium emerged as one of the four capital cities of the Roman Empire, the other three being Trier, Mediolanum, and Nicomedia and was the capital of Emperor Galerius. With the establishment of Praetorian prefectures in 318, the capital of the prefecture of Illyricum was Sirmium, remaining so until 379, when the westernmost Diocese of the Praetorian prefecture of Illyricum, Pannonia (including Sirmium), was dettached and joined to the Praetorian prefecture of Italia assuming the name of Diocese of Illyricum. The eastern part of Illyricum remained a separate prefecture under the East Roman Empire with its new capital in Thessalonica.
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From the 4th century, the city was an important Christian center, and the seat of the Bishop of Sirmium. Five church councils, the Councils of Sirmium, were held in Sirmium. The city also had an emperor's palace, horse racing arena, mint, arena theatre, theatre, as well as many workshops, public baths, temples, public palaces and luxury villas. Ancient historian Ammianus Marcellinus called it "the glorious mother of cities".
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At the end of the 4th century, Sirmium was brought under the sway of the Goths, and later, was again annexed to the Eastern Roman Empire. In 441, Sirmium was conquered by the Huns, and after this conquest, it remained for more than a century in the hands of various other tribes, such as Eastern Goths and Gepids. For a short time, Sirmium was the centre of the Gepid State and King Cunimund minted golden coins there. After 567, Sirmium reverted to the Eastern Roman Empire. The city was finally conquered and destroyed by the Avars in 582.


(AVAR RULE)      (Eurasian Avars)      (Avar Khaganate)      (Siege of Sirmium)


(Maurice Balkan Campaigns)      (Singidunum)      (Tiberius II Constantine)

(panacomp.net/Serbia - Sirmijum)      (Edward Gibbon, The Decline and Fall of the Roman Empire)

Baynes, Norman H. (1913), "Chapter IX. The Successors of Justinian", The Cambridge Medieval History, Vol. II: The rise of the Saracens and the foundation of the Western Empire, New York: Cambridge University

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