(Collecta: S. Giorgio)
(Image source)
From the Churches of Rome wiki:
The church was one of the tituli, the first parish churches of Rome, known as the Titulus Chrysogoni. It was probably built in the 4th century under Pope Sylvester I (314–335), rebuilt in the 12th century and again by Giovanni Battista Soria, funded by Scipione Borghese, in the early 17th century.
The area beneath the sacristy was investigated by Fr. L. Manfredini and Fr. C. Piccolini in 1907. They found remains of the first church. After they had made this discovery, the area was excavated and studied.
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The interior of the present church is the result of the rebuilding in the 1620's of the 12th century church. The 22 granite columns are ancient.
The floor is Cosmatesque, but most of it is hidden by the pews.
The confessio in the sanctuary area is from the 8th century. The high altar is from 1127, with a baldachino from 1627 by Gian Lorenzo Bernini.
The painting in the middle of the Baroque coffered ceiling is by Gian Francesco Barbieri, and depicts the Glory of Saint Chrysogonus. It may be a copy, in which case the original was taken to London, but it might also be vice versa.
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Remains from the first church, possibly from the reign of Constantine, and earlier Roman houses can be seen in the lower parts, reached by a staircase in the sacristy. The ruins are confusing, but you can easily find the apse of the old church and you can see the remains of the martyr's shrine in middle of the apse wall. The church had an uncommon form; rather than the normal basilical plan with a central nave and two aisles on the sides, it has a single nave.
Fresco of St. Benedict curing a leper, found in the excavations beneath the later medieval basilica of S. Crisogono
