The Lombardian city of Bergamo is composed of two parts, Città Alta (Upper Town), built up on the hills, and the Città Bassa (Lower Town), which is a lively financial, industrial and administrative centre of national importance.
A milestone in the history of Bergamo was its incorporation into the Venetian State in 1428, which lasted for over three centuries and a half. The two parts of city are separated, both physically and symbolically, by the powerful Venetian Walls, which were built by the Serenissima Republic of Venice in the second half of the 16th century to defend the city, which was the farthermost centre on the Mainland, close to the border with Milan's territory.
The walls never underwent any siege. That is why they remained almost intact to the present day. The system consist of 14 bastions, 2 platforms, 100 embrasures for cannons, 2 armouries, four gates, not to mention the underground structures featuring sallies, passages and tunnels.
The Arch of Constantine is situated between the Colosseum and the Palatine Hill. It was erected by the Roman Senate to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge in 312. Dedicated in 315, it is the largest Roman triumphal arch. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.
Though dedicated to Constantine, much of the decorative material incorporated earlier work from the time of the emperors Trajan (98-117), Hadrian (117-138) and Marcus Aurelius (161-180), and is thus a collage. The last of the existing triumphal arches in Rome, it is also the only one to make extensive use of spolia, reusing several major reliefs from 2nd century imperial monuments, which give a striking and famous stylistic contrast to the sculpture newly created for the arch.
The arch is 21 m high, 25.9 m wide and 7.4 m deep. Above the archways is placed the attic, composed of brickwork reveted (faced) with marble. A staircase within the arch is entered from a door at some height from the ground, on the west side, facing the Palatine Hill. The general design with a main part structured by detached columns and an attic with the main inscription above is modelled after the example of the Arch of Septimius Severus on the Roman Forum.