The white marble Arch of Septimius Severus at the northwest end of the Roman Forum is a triumphal arch dedicated in AD 203 to commemorate the Parthian victories of Emperor Septimius Severus. and his two sons, Caracalla and Geta.
After the death of Septimius Severus, his sons Caracalla and Geta were initially joint emperors. Caracalla had Geta assassinated in 212; Geta's memorials were destroyed and all images or mentions of him were removed from public buildings and monuments. Accordingly, Geta's image and inscriptions referring to him were removed from the arch.
The arch was raised on a travertine base originally approached by steps from the Forum's ancient level. The central archway, spanned by a richly coffered semicircular vault, has lateral openings to each side archway, a feature copied in many Early Modern triumphal arches. The Arch is about 23 metres in height, 25 metres in width and 11.85 metres deep.References:
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.