The small Chapel of St. Zeno,off the east aisle in the church of Santa Prassede, was built as a mausoleum for Pope Saint Paschal I’s mother Theodora. It is the only chapel in Rome entirely lined with mosaics. All are original to the 9th-century basilica. They are made almost exclusively of fine glass tesserae, which may have been taken from earlier mosaics.

All that is known about Zeno is that he was bishop of Verona (361-72), a trained orator and ardent preacher. His relics were among those brought from the catacombs by Pope Paschal.

The chapel is entered through a doorway flanked by ionic columns with 9th-century capitals, which support a 1st-century sculptured cornice. The cornice is inscribed with Paschal’s monogram and inscribed with the dedicatory inscription:

PASCHALIS PRAESVLIS OPUS DECOR FVLGIT IN AVLA QVOD PIA OPTVLIT VOTA STVDVIT REDDERE DO (Ornament shines in the hall, the work of the prelate Paschal, because he made devout prayers and was earnest in paying this due to the Lord).

Inside, the Chapel of St. Zeno is cross-shaped and based on the plan of early pagan and Christian mausoleums. It also resembles a cubiculum (small room) in the catacombs. The walls are covered in marble (original but restored) and the floor is opus sectile, with a large porphyry disk in the center. The columns are Roman.