A complete guide to the St Agnes extra moenia and Mausoleum of St Costanza, in a handy format to accompany the visitor in the discovery of one of the most important ancient basilicas in Rome.

The monumental complex of St Agnes is located on the Via Nomentana in the north-east of Rome. The site consists of an underground cemetery (catacombs), the remains of the ancient circiform sepulchral basilica, commissioned by the imperial family of emperor Constantine, the mausoleum dedicated to St Constance and the basilica of St Agnes Outside the Walls, built by Pope Honorius I (625-638) on the small room with an altar, venerated as the burial place of the martyr Agnes.

The mausoleum dedicated to St Constance, which houses the remains of the imperial princess Constantine, is a splendid example of late antique architecture. The deambulatory is covered by a sumptuous mosaic decoration with Hellenised geometric motifs and cosmic-seasonal phytomorphic and zoomorphic elements, symbolic scenes such as the harvest and portraits of historical figures.

The basilica of St Agnes, until the beginning of the 17th century, was below ground and to reach the ground floor a staircase was used. The basilica still retains many elements unchanged from the time of Pope Honorius: the splendid reused roman columns, the famous mosaic showing Agnes between Honorius I and Pope Symmachus, and the Proconnesian marble and porphyry facing of the apse... Above the high altar is the statue of St. Agnes, made by Nicolas Cordier from gilded metal, using an ancient oriental alabaster for the bust.