Santa Costanza

Location

Santa Costanza is located a minute's walk to the side of the Via Nomentana, the road that follows the ancient Roman route running north-east from Rome to Nomentum or Mentana. It lay a short way outside the ancient walls of Rome in a cemetery area, and probably in an Imperial family estate. The underground catacombs had been built there many years earlier and contained the relics of Saint Agnes who was martyred as a thirteen-year-old, and over whose tomb was a small chapel.

History

The funerary hall or "Constantinian basilica" was built first from 338 as a result of Constantina's devotion to Saint Agnes, a legend later considerably elaborated, but early Christians believed that their souls benefited from being buried close to martyrs, which was almost certainly a major attraction of the funerary hall to those who paid to be buried in it.

The mausoleum was built around 350, as shown by excavations in 1992 which discovered an earlier building beneath which may have been the baptistry built by Constantine (at the same time as the funerary hall), in which Constantina and her paternal aunt were baptised by Pope Silvester I (d. 335), as recorded in Liber Pontificalis.

Annexing an important mausoleum to a basilica was a common practice at the time, as seen in the Mausoleum of Helena (Constantine's mother) attached to the basilica of Santi Marcellino e Pietro ad Duas Lauros on Via Labicana (today Via Casilina). Other basilicas with floorplans typical of the Constantine era are San Sebastiano fuori le mura on Via Appia, San Lorenzo fuori le mura on Via Tiburtina and the anonymous basilicas on Via Prenestina and Via Ardeatina, the latter recently discovered and attributed as the burial place of Pope Mark (d.336).

The bodies of the sisters were both brought considerable distances to be buried there: Ammianus records that Constantina's body was brought back from Bithynia, and Helena's from Gaul.

The Constantinian basilica gradually fell out of use and into ruins, with the base of the wall now surviving for about a third of the original circuit of exterior walls, but Santa Costanza has survived all but intact. It is documented that Pope Nicholas I celebrated mass there in 865, the first time that "Santa Costanza" is recorded as its name, but its consecration as a church was not until 1254, by Pope Alexander IV, who had what were believed to be the remains of Constantia removed from the larger sarcophagus and placed under a central altar.

Architecture

The structure of Santa Costanza reflects its original function as the mausoleum of one or both Constantine's two daughters, Constantia and Helena, rather than as the church it became much later. The centralized design put "direct physical emphasis on the person or place to be honored" and was popular for mausoleums and places of baptisms at this time. Other early Christian buildings with a similar origin and a circular plan include Split Cathedral, built within Diocletian's Palace as his mausoleum, and the Rotunda of Galerius (now the Church of St. George) in Thessaloniki built as a mausoleum for Galerius.

Santa Costanza is a circular, centralized structure, with a circular ambulatory ringing a high central space topped by a shallow dome, which is raised on a round drum, as can be seen from the exterior. It is built of brick-faced concrete and its structure is basically two rings supported by columns placed around a vertical central axis. The upper ring sits on the columns while the "lower ring encloses a circular ambulatory whose space flows between the columns into the axial cylinder." This design essentially creates two spaces or two worlds, that of the ambulatory and that of the upper dome. The screens of the ambulatory and inner ring create a dark contrast to the bright upper space of the dome. This contrast of light can be seen in the picture of the main interior. The single door, flanked by two arched niches, would originally have been an internal arch or doorway leading straight into the Constaninian basilica or funerary hall, half-way along its length. There is a short vestibule inside the door, opening to the ambulatory.

An arched arcade with twelve pairs of granite columns decorated with composite capitals supports the drum below the dome, and separates the area of the ambulatory beyond, which is much darker, as light from twelve windows in the clerestory does not reach this area as well. In contrast, the central area is well-lit, creating interplay between dark and light in the interior. …

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.