### CONSTANTIA, MAUSOLEUM OF SAINT
It was built by Constantina or Costanza, daughter of the emperor CONSTANTINE, as her mausoleum, when around 337 she settled in the preadium on the Via Nomentana (cf. F. Savio, Costantina figlia dell’imperatore Costantino Magno e la basilica di S. Agnese a Roma, in Atti dell’Accad. delle Scienze di Torino, 42 [1907], pp. 659, 732). Recent elements brought to light may confirm its use also as a baptistery. In a period distinct from that of its construction, the elliptical buttressed enclosure was added, which delimits a burial ground. When transformed into a church, it appears to have been restored in the time of Innocent III; Alexander IV consecrated an altar there (1256). From the Renaissance artists, who often depicted it in their drawings, the building was considered a temple of Bacchus. At the beginning of the 17th century (1620) it was restored by Cardinal Fabrizio Veralli, who destroyed the remains of mosaics on the dome.
The construction has a circular plan, preceded by a narthex with a forked entrance; twelve pairs of columns arranged radially and at somewhat irregular intervals, so as to suggest a cross, are connected by arcades on which the drum with wide arched windows and the dome are set. The latter is of brick ribbing with meridian ribs connected by a concrete pour. Between the central space and the perimeter wall runs an ambulatory.