During the 5th century AD, a large part of Bologna was abandoned. There was general degradation in the city. The Roman administrative and political structures of the city had been dissolved.
During this period of decline Bologna was brought under the reigns of the barbarian kings Odoacre (the first King of Italy from 476 -493) and Teodoric (King of Italy from 493 – 526) until Justinian (482-565), who travelling from Byzantium hunted and defeated the Goths thus restoring the Roman empire.
As a result, Bologna was returned to the Roman Empire of the East. This is the beginning of the Byzantine period of Ravenna (568).
From hereonin until 15o years later, Bologna becomes the defence line against the Lombards until 727 when Liutprand conquers the city
Bologna now is incorporated into the Lombard Kingdom. The Germanic conquerors formed a district called “addizione longobarda” near the complex of S. Stefano.