by the imperial family, whose colour purple was. It was quarried from only one place, Mons Porphyriticus (Coptos, Egypt), making it even more exclusive. It appears, but can not be certain, that the sarcophagus of Constantina is a copy of that of Constantine I, her father, which is now lost. A piece of what is believed to be his sarcophagus is similar in style and of the same material. A cast replica has been placed in the church, though in the ambulatory; presumably its original position was in the centre of the church, now occupied by the altar. There is another in the Museum of Roman Civilization in the city. Alternative views Some consider that the building was only later reassigned as a church dedicated to Santa Costanza. The veneration of Constantina as "Santa Costanza" (Saint Constance) is only known from the 16th century onward, and her name is not included in the Roman Martyrology. An original structure might be located underneath the current church, as a possibly triconch-shaped structure was partially excavated in 1987 and 1992 and computer-reconstructed by David J. Stanley. That could suggest that the current church is the second Christian building on the site, and may be some decades later than traditionally thought, being built as a mausoleum for Constantina's sister Helena in the reign of her husband Julian the Apostate. (This would be odd, however, because Julian was a staunch pagan.) If true, the larger of the two porphyry sarcophagi there would belong to Helena, and the smaller to Constantina, the opposite of what has been traditionally thought. The earlier triconch building of the 330s was probably indeed built for Constantina, but she later had to take second place to her sister. Then, as Constantina's fame as a saintly figure developed in the Middle Ages, their roles became reversed in the popular mind. See also Architecture of ancient Rome Early Christian sarcophagi Early Christian art and architecture History of Roman and Byzantine domes Notes References Further reading Blasen, Philippe Henri, "De sancta Agnete Romana e fontibus Latinis antiquissimis... Sainte Agnès de Rome dans les sources latines les plus anciennes jusqu'à Augustin d'Hippone", Acta Musei Napocensis 45–46 (2011): 253–281. Stanley, David J., "New Discoveries at Santa Costanza", Dumbarton Oaks Papers 48 (1994): 257–261. Weitzmann, Kurt, ed., Age of spirituality: late antique and early Christian art, third to seventh century, no. 108 & 246, 1979, Metropolitan Museum