Arch of Constantine, Rome, south front.

The Arch of Constantine (Italian: Arco di Costantino) is a triumphal arch in Rome, 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, and the latest existing triumphal arches in Rome, it was also the only one to make extensively reuse major sculpture from earlier monuments. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.

more on https://en.wikipedia.org/wiki/Arch_of_Constantine

picture generously provided by Rudolf Kaufmann (2015)