San Crisogono is a 12th century parish, titular and conventual church, and a minor basilica in rione Trastevere. The dedication is to the martyr
St Chrysogonus. The complex includes remains of a 4th century church edifice.
For reference, a plan of the church is available
here.
Its origins date back to the fourth century and are probably closely related to the Roman domus in which San Crisogono was taken prisoner before his martyrdom. The original church, now over five meters below the present one, was not discovered until 1907.
In 1123 Cardinal Giovanni da Crema abandoned the old dilapidated church, removed the roof and the walls above five meters, packed the interior with earth and built a new basilica-style church on top.
In 1626 Cardinal Scipione Caffarelli Borghese, nephew of Paul V, completed his uncle's project of a major restoration of the church, appointing
Giovanni Battista Soria to the task.
In 1847 the church was given into the care of the Discalced Trinitarians, whose emblem of a red and blue cross can be seen throughout the church, the result of subsequent restorations in the 19th century.