In the adjoining crypt was the tomb of St.Cecilia, the popular patron saint of music. Of a noble Roman family, she was martyred in the 3rd c. and entombed where the statue now lies. She was venerated in this crypt for at least five centuries. In 821 her relics were transferred to Trastevere, in the basilica dedicated to her.
The statue of St.Cecilia is a copy of the celebrated work sculptured by Stefano Maderno in 1599.
The crypt was all covered with mosaics and paintings (beginning of the IX Century). On the wall, near the statue, we see an ancient painting of St.Cecilia in an attitude of prayer; lower down, in a small niche, is a fresco representing Christ holding a Gospel. On the right side is the figure of St.Urban. On the wall of the shaft is the painting of three martyrs: Polycamus, Sebastian and Quirinus.