The ancient church of Santa Cecilia in Trastevere was built by Pope Paschal I (r. 817-24) to house the remains of St Cecilia and her husband St Valerius, which were transferred to the church from the catacombs of San Callisto in 820.
Paschal I appears in the mosaic in the apse; his halo is square to show that he was still alive when the mosaic was made. Above his halo, perched on a branch of a palm tree, is a phoenix, a symbol of the Resurrection. In the centre of the mosaic stands Christ with St Paul, St Agatha (wearing a crown) and Paschal I on the left and St Peter, St Valerian and St Cecilia on the right. At the lower level twelve lambs (representing the Apostles) emerge from the cities of Bethlehem and Jerusalem and converge on the Agnus Dei.
On October 20th 1599, during the course of restoration work in the church, two marble sarcophagi were discovered. Cardinal Sfrondato, the titular cardinal of the church, had the sarcophagi opened before the presence of witnesses. In one of the sarcophagi was a wooden casket, which contained the body of St Cecilia. Peering through the veil, which covered her body, they noted that the saint was small of stature and that her head was turned downward.
A young sculptor, Stefano Maderno (1576-1636), was commissioned to depict the saint's body exactly as it was found. Maderno's sculpture is on display in a striking black marble recess, under the high altar.
The interior was transformed in the early 18th century when grilles were added in the upper gallery to allow the nuns to attend services. At the same time the facade was designed by the Florentine architect Ferdinando Fuga (1699-1782).
St Cecilia, Virgin and Martyr, is thought to have lived in the second or third century. Her feast day is celebrated on November 22nd and she is the patron saint of musicians.