Sirmium, Siege of
Years: 580 - 582
The Siege of Sirmium in 580–582 is a decisive event in the history of the Balkans.
The fall of the city to the Avars deprives the Byzantine Empire of its major stronghold on the northwestern Danube, opening the path for devastating incursions by the Avars and their Slavic allies into the Balkans.
