What to see
The church features a basilical layout with an inscribed transept and a three-nave body covered by wooden trusses. The raised transept is cross-vaulted and aligns with the width of the naves, leading to the central apse. The lower section of the façade, completed in 1210 by master Filippo as recorded in the lunette inscription, is decorated with blind arches containing 17th-century ceramic bowls. It houses three Byzantine bas-reliefs brought from Constantinople, depicting the praying Virgin, the Archangel Gabriel, and a peacock. The upper façade was rebuilt in brick following a 1690 earthquake. Master Leonardo sculpted the symbolic vine motifs decorating the main splayed portal, while the right side features a later secondary portal with a Gothic sculpture of the Visitation. 20th-century restorations removed later Baroque additions and unveiled the original Romanesque lines.
Visiting
Visitors can explore the underlying 4th- and 6th-century Palaeo-Christian basilica either by descending two flights of stairs or viewing it through glass panels inserted into the upper church floor. The archaeological zone preserves two overlapping layers of polychrome mosaics adorned with acanthus leaves and birds, alongside porphyry column drums, fragments of frescoes, an ancient well, remnants of early altars with reliquary niches, and sections of Hellenistic and late-antique city walls. The building was famously depicted in a 1936 woodcut by Dutch artist M.C. Escher and a 1925 engraving by Bruno da Osimo.
Our editors' tip
Look closely at the glass floor openings inside the nave to appreciate how the medieval Romanesque building was constructed directly on top of the ancient Palaeo-Christian mosaic floors.