Bologna (also known as Bononia, Felsina and Felzna throughout history) had a strategic geographical position between the powers which lay to the north and south of the Italian peninsula. But she also lay in a strategic position when it came to the East. At the end of the Roman Empire and the beginning of the Christian Empire with the transfer of power from Rome to Ravenna, the importance of Bologna continued.
This geographical strategic position meant that also politically, Bologna was in a position to influence the happenings between North, South and East. Who held Bologna, was definitely in a stronghold position. Not ignoring this and to protect the city, the inhabitants built walls. In fact, they built three (3) fortified walls around the heart of the city, which began from an inner circle around the heart of the political centre and circled out to also protect its most important inhabitants who resided within these walls. One could access passing through one of its twelve doors.