Daughter of Emperor Constantine I,
Constance had her own Mausoleum built in Rome, on the Via Nomentana, between 337 and 351 AD, next to a large basilica of which few ruins remain, because it was abandoned in the 7th century.
The Mausoleum was mentioned as such for the first time in official documents of the eighth century, and in 1256 it was consecrated to Santa Costanza.
Constance died in Antioch in 354 AD. and was
buried in Rome in her Mausoleum together with her sister Helena (who should not be confused with Saint Helena, mother of Constantine).
Her sarcophagus in precious red porphyry was moved to Piazza S. Marco between 1467 and 1471 and in 1790 it was transported to the Vatican Museums, with a cart pulled by 40 oxen. In modern times a copy has been placed in the Mausoleum.
The sarcophagus is decorated with Dionysian symbols and peacocks which are a symbol of immortality, as centuries before were
the gilded bronze Peacocks of the Mausoleum of Hadrian (Castel Sant'Angelo), of which two examples remain; once they decorated the Cortile delle Pigna in the Vatican Museum.
Red porphyry, whose color alludes to purple,
was the imperial stone par excellence, used for the sarcophagi of Roman emperors, including Hadrian himself.
Given that in some mosaics there are vine swirls and scenes of grape harvest, for a long time it was thought that in pagan times the building had been a temple dedicated to Bacchus or Dionysus. Actually, the harvest scenes allude to the evangelical similarities of the vineyard and the vine, and in practice a new meaning was given to a very ancient iconography.
The vine is in fact identified with Jesus, while the Father is the vinedresser. The culmination of the symbolism of wine occurs in the Last supper, when Jesus, taking the cup with wine, states that that wine is his blood, shed for all.
The Mausoleum has a ring-shaped corridor with a barrel vault, with 14 niches and 17 small windows that revolves around a central space delimited by 12 pairs of columns and covered by a dome in which 12 windows open.
The building was completely covered with polychrome mosaics, partly preserved. The magnificent mosaics of the ring corridor were restored in the 19th century: they have geometric patterns, animals, birds and vegetal elements, grape harvest scenes, swirls with clipped images.
Unfortunately, in the eighteenth century the mosaics of the dome were replaced by a fresco, because they were badly damaged. The pavement was also replaced.
The walls were covered with polychrome marbles which are completely lost; in two of the side niches mosaics depicting Jesus giving the keys to Saint Peter or Jesus between Saints Peter and Paul are partially preserved.