The apse mosaic, which I have photographed over four days and in different lights to emphasize the changes of colour that can occur, dates from the end of the 4th century during the pontificate of Innocent I. They were restored in the 16th century. They are among the oldest Christian mosaics in Rome and one of the most striking mosaics outside of Ravenna. They were deemed the most beautiful mosaics in Rome by the 19th century historian Ferdinand Gregorovius.
This mosaic is remarkable for its iconography. Christ is represented as a human figure rather than as a symbol, such as lamb or the good shepherd, as He was in very early Christian images. The regal nature of this representation prefigures the majestic bearing of Christ as depicted in Byzantine mosaics. Christ sits on a jewel encrusted throne, wearing a golden toga with a purple trim (a sign of imperial authority and emphasizing the authority of Christ and His Church). He poses as a classical Roman teacher with His right Hand extended. Christ wears a halo and holds in His left Hand the text : “Dominus conservator ecclesiae Pudentianae” (The Lord is the preserver of the church of Pudenziana). He sits among his apostles, two of which have been removed during restoration. The apostles wear senatorial togas. They all have individual expressions and face the spectator. The lower part of the mosaic has been removed during the restoration in the late 16th century. The mosaics of the apostles on the right side have been lost in the course of time and are replaced by new, but rather blank, mosaics. Two female figures (representing “Church” and “Synagogue”) hold a wreath above the head of St. Peter and Paul. Above them the roofs and domes of heavenly Jerusalem (or, in another interpretation, the churches built by the emperor Constantine in Jerusalem) are depicted. Above Christ stands a large jewel encrusted cross on a hill (= Golgotha), as a sign of the triumph of Christ, amidst the Christian symbols of the Four Evangelists. These iconographic symbols (angel, lion, ox and eagle) are the oldest still existing representations of the Evangelists. The backdrop is a blue sky with an orange sunset.
