o 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 t