This is one of the most beautiful bridges of the Roman aqueducts, the most impressive and best preserved. It was built to allow the ditch of the Aquamaraming to pass the aqueduct of the Anio Novus (38-52 AD), in effect a deep and impervious gorge. Originally the bridge was less "massive" and its arches were more "slender". It consists of a central arch 30 meters high, supported at the ends by powerful containment and support works, and two series of arches, for a length of 120 meters. The original structure was in Claudio's time in tuff blocks and covered in opus reticulatum. Subsequently, during the 4th and 5th centuries AD, consolidation works were carried out with the massive use of cement works and brick coverings, and the creation of sub-archings. These interventions covered the original building and reduced, as mentioned, the light of the arcuations. The bridge takes its name from an image of Sant'Antonio which may have been located there in the 17th century.