The Church of Santa Costanza in Rome, physically connected with the ancient cemetery church of Santa Agnese, was originally a mausoleum. It was built in the early 4th century, and consecrated as a church in 1254 by Pope Alexander IV. A restoration in 1620 by Cardinal Veralli destroyed most of the mosaics in the central dome. The remaining dome mosaics were destroyed in a 19th century restoration project. Archaeologists seem to agree that this is one of the most intact Roman structures of its period, standing generally as it was built, with exception of loss of an external colonnaded ambulatory, some remains of which can still be seen. The structure is known for the mosaics that have survived, although heavily restored, in two small apses and along the entire length of its barrel-vaulted ambulatory. The mosaics along the ambulatory are original, although restored. The apse mosaics are of a more recent style, and both appear to be the product of the same artist, but almost certainly a different artisan from the one responsible for the ambulatory mosaics. The two groups, apse and ambulatory, are radically different in both style and content.

The mausoleum once held a large porphyry sarcophagus, known as the Sarcophagus of Constantina, now in the Vatican Museum. A replica now stands in its place. This sarcophagus may have been made for Constantine's daughter, Constantina. This seems to be the best theory, although Karl Lehmann (1955) identified a number of problems with it, related to Constantina's location and interests at the time of her death. None of the decorations of the sarcophagus indicate the gender of its owner. They include winged erotes who are harvesting grapes and making wine, along with sheep, peacocks and doves. These images are more consistent with a pagan origin than a Christian one, despite the fact that all these images can appear along with biblical scenes on Christian sarcophagi. Because Christians were no doubt buried in sarcophagi made in generic non-Christian shops, the only indication of Christian usage might be the inscription or secondary addition of a chi-rho symbol or labarum. In other cases, partially-completed, "generic" sarcophagi were finished with the addition of Christian scenes the central panels. In such cases, it would be more accurate to state that Christians were able to tolerate certain pagan images on their sarcophagi than that Bacchic grape harvest scenes were Christian images. In the case of the Constantina Sarcophagus, there is virtually nothing to indicate that its owner wasn't pagan, besides late Christian legends.

The mosaics of the ambulatory include typical Bacchic grape harvest and winemaking scenes. While there is evidence of considerable sharing between Christian and pagan symbols of this period, there is no basis for a Christian interpretation to these mosaics, despite claims to the contrary by apologists and some writers focused on Christian lore. A Christian interpretation of these mosaics would require total redefinition of Christian/pagan iconography, and would result in a completely arbitrary boundary between these and other similar artworks known to be strictly pagan - particularly those from the pre-Christian era. Joseph Wilpert's (1916) claim that a Christian origin of these mosaics was universally accepted was false at the time (besides being of essentially an argument from authority to start with), but has been the basis for similar claims in the last century, resulting in the present state of common understanding of the structure's origin. In fact, it appears that the 16th century scholars who saw these and the now-destroyed dome mosaics in person universally concluded the structure and its mosaics were of pagan origin. A motive for the modern insistence on Christian origin might be the desire to associate all things Constantinian with Christianity, while the evidence suggests that Constantine carefully balanced his Christian and pagan alliances.

Two apse mosaics in Santa Costanza appear to depict Jesus. They are ancient, although heavily restored. They do not appear to be related to the somewhat older mosaics in the ambulatory.

The mosaics appear to show Jesus in both his early forms, the young blonde-haired shepherd and the older man on a throne with dark hair and beard. The young Apollo-like Jesus was the first to appear in Christian art - at least a century before the dark-haired, Syrian, version. The blonde Jesus wears a light-colored tunic and cloak (pallium). The scene is a common one from Christian art of the period - Jesus as shepherd, handing the scroll of the new law to Peter and Paul. One possible departure from this common theme is that it does not appear that Peter, Paul and Jesus are in heaven, standing on the firmament as they usually appear on sarcophagi, but are perhaps on the rock of Calvary. (Neither in scripture nor in Catholic tradition did Paul encounter the earthly Jesus.) In the other mosaic Jesus wears purple and gold, indicating a more regal role. It is possible that the latter was meant by the artist to represent God the Father. Early Christians may have confused the two images, resulting in the transition to the dark-haired Jesus image popular today.

Joseph Wilpert, Die römischen Mosaiken und Malereien der kirchlichen Bauten, Frieburg i/Br., 1916., cited in Lehmann (below) and in Vatican Museum placards.

Karl Lehmann, "Sta. Costanza", The Art Bulletin, Vol. 37, No. 3 (Sep. 1955) pp. 193-196.