Visible are round reliefs dated to the times of Emperor Hadrian. This side, left to right; departure for the hunt, sacrifice to Silvanus, hunt of a bear, sacrifice to Diana. The head of the emperor (originally Hadrian) has been reworked in all the medallions.

Erected to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge on October 28, 312. Dedicated in 315, it is the latest of the existing triumphal arches in Rome. The arch is heavily decorated with parts of older monuments (spolia), which assume a new meaning in the context of the Constantinian building. Elements from monuments of Trajan, Hadrian and Marcus Aurelius have been incorporated. The most famous are the round reliefs (four on each long side) that are Hadrianic.