- UNESCO
- Free 1st Sunday
Photo: No machine-readable author provided. MM assumed (based on copyright claims)., Public domain · Wikimedia Commons
Archaeological site
Arch of Janus
Ancient building in Rome
- Within the UNESCO World Heritage Site “Historic Centre of Rome, the Properties of the Holy See in that City Enjoying Extraterritorial Rights and San Paolo Fuori le Mura”
At a glance
- Type
- Archaeological site
- Coordinates
- 41°53′22″ N, 12°28′58″ E
History and description
The Arch of Janus is the only quadrifrons triumphal arch preserved in Rome. It was set up in the early 4th century AD at a crossroads at the northeastern limit of the Forum Boarium, close to the Velabrum, over the Cloaca Maxima drain that went from the Forum to the River Tiber.
The significance of the arch is poorly understood: it is thought to have been a boundary marker rather than a triumphal arch. An alternative view is that it was built to provide shelter for the traders at the Forum Boarium cattle market. Some researchers believe it was dedicated to Constantine I or Constantius II and was known as the Arch of the deified Constantine. It is 16 meters high and 12 meters wide; it was originally higher, but the attic storey was removed in 1830 in the erroneous belief it was all medieval.
Its modern name probably dates from the Renaissance or later, and was not used to describe it in classical antiquity. The name is derived from the structure's four-fronted, four-arched configuration. The ancient Roman god Janus (Ianus Quadrifons), was sometimes depicted with four faces and there are Janus-related structures mentioned in historic descriptions of ancient Rome.
History
It was built using spolia, i.e. material from earlier buildings, including bricks, together with pottery shards, and was covered with white marble, also from earlier buildings.
In the Middle Ages, the Frangipane family transformed the building into a fortress, and so it survived intact until 1830. Then, the attic and top were torn down because they were erroneously believed to not belong to the original structure. However, there is a staircase within the north-west pier which would have given access to this top floor. Iron pins originally held together the marble blocks but were removed in the Middle Ages, leading to the monument's present pock-marked look. Fragments of the dedicatory inscription are still preserved inside the nearby church of San Giorgio in Velabro.
The arch has not been accessible to the public since the explosion of a bomb in front of San Giorgio in Velabro, on the night of 27 July 1993. It is the one monument of the Forum Boarium that remains unrestored. The Arch of Malborghetto, just outside Rome, also includes the remnants of a former Roman quadrifons arch.
Text from Wikipedia, the free encyclopedia, under CC BY-SA 4.0. Full article: «Arch of Janus».
Photos
Getting there
Roma OstienseTrain, nearest
2.0 km as the crow flies
Arch of Janus
Aeroporto di Roma-Ciampino13.5 km
Distances are as the crow flies, not walking or driving.
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Nearby
See on the mapMore archaeological sites in Lazio
- Free 1st Sunday
- Free 1st Sunday
- UNESCO
Frequently asked questions
Where is Arch of Janus?
Arch of Janus is in Rome, in the province of Roma (Lazio), Italy. GPS coordinates: 41.88944, 12.48278.
What else is there to see near Arch of Janus?
Nearby you’ll find: Museo della Camera storica (100 m away), Museo della confraternita di sant'Eligio dei Ferrari (100 m away), Circus Maximus Mithraeum (100 m away).
Sources and licences
Text. Wikipedia, the free encyclopedia (CC BY-SA 4.0).
Data. Wikidata (CC0); opening hours and contacts OpenStreetMap (ODbL).
Photos. Wikimedia Commons, author and licence on every image.
Credits for the 9 photos
- RomaArcoGianoCostantino2 — No machine-readable author provided. MM assumed (based on copyright claims)., Public domain
- Arch of Janus (Arco di Giano) - Rome, Italy - DSC00566 — Daderot, Public domain
- 2012-06-23 Roma Arco di Giano — Blackcat, CC BY-SA 3.0
- 2016 Arco di Giano — Jordiferrer, CC BY-SA 4.0
- Arch Of Janus - Flickr - Me in ME — Paul VanDerWerf from Brunswick, Maine, USA, CC BY 2.0
- Arch of Janus - panoramio — trolvag, CC BY-SA 3.0
- Arch of Janus (Rome) 01 — Nicholas Gemini, CC BY-SA 4.0
- Arch of Janus in 2007 — No machine-readable source provided. Own work assumed (based on copyright claims)., Public domain
- Arch of Janus-Rome — Yair Haklai, CC BY-SA 3.0
Updated 28 October 2026. All sources and licences