The Sarcophagus of St. Helena

The Sarcophagus of St. Helena, who died in 329, is the red porphyry coffin of the mother of Emperor Constantine the Great. The remains have been lost to antiquity and the coffin was removed from the Mausoleum of Helena, just outside Rome and moved to the Vatican museums in the 18th century.

The Sarcophagus is carved in the Egyptian porphyry, which is a decorative granite, used in many Byzantine imperial monuments. The imagery depicts victorious Roman cavalry riding above captured barbarians.

The second sarcophagus is that of Constantina, the daughter of Constantine the Great, who died in 354. Her mausoleum became the church of Santa Costanza in 1254, and later the coffin was moved again to the Vatican museums. The decoration is a semi-pagan depiction of cupids harvesting of grapes to make wine; which is perhaps an early Christian reference to the Eucharist.

Description via:

The Metropolitan Museum of Art Guide, ed. Philippe De Montebello and Kathleen Howard, pp. 176–177.