Santa Maria in Trastevere is one of the oldest churches in Rome. It was probably built in the early fourth century, although legend states that it was founded by Pope Callixtus I (whose remains are buried under the altar) in the 3rd century. The body of this Romanesque church dates from the 1100s. The 22 granite columns in the nave came from the ruins of ancient Roman buildings.

Inside the church are a number of mosaics by Pietro Cavallini on the subject of the Life of the Virgin (1291).

The facade of the church was restored by Carlo Fontana in 1702.

The octagonal fountain in the piazza in front of the church (Piazza di Santa Maria in Trastevere) was also restored by Carlo Fontana in the 17th century.