ew 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.
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.
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.
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.
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.
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