Three. 32). ¹⁰² The apse itself is a robust building positioned on the fringe of the terrace it stocks with Santa Costanza and consequently requiring deep foundations underneath it. it's preserved to a peak of 2 tales. the internal was once 94          ,         ,          illuminated by means of huge home windows in either facet partitions and apse right. The construction is understood in basic terms in its barest outlines. It measures ninety eight m in size and forty m in width. The plan is equal to that of the basilica of the through Labicana with the addition of an atrium earlier than the doorway. There also are foundations for a moment apsidal enclosure in the curve of the ambulatory colonnade. The church of Santa Costanza within the parklike environment of the through Nomentana, miles open air the Aurelian partitions of Rome, seems a nearly unchanged survival of the Constantinian age (fig. three. 33). The around development is whole shop for what used to be supported on an outer ring of foundations. it's hooked up to the apse-ended basilica by way of an elliptical fore chamber. at the inside, the ambulatory with its barrel vault wearing its well-known mosaics opens to the heart via a sequence of arches supported by way of pairs of columns instead of through piers (fig. three. 34). The columns have conscientiously selected yet no longer matching Corinthian capitals. the hoop of arches helps the drum, which supplies a spacious top to the inner and lightweight via its huge home windows. the inner diameter is 22. five m, and the drum rises to a peak of nineteen m above the floor (fig. three. 35). right here, if anyplace, is a flavor of an inside of Constantinian Rome alive with the colour and the interlacing designs of its mosaics within the vault over the ambulatory. The shadow of the hall makes a wise distinction with the openness and light-filled quantity of the drum, whose weight is carried so simply by means of the arches and small columns setting apart them. eventually, within the oblong area of interest at once throughout from the doorway, there stood the grand porphyry sarcophagus decorated with cupids tramping out the classic. Briefly got rid of in 1467–71, it has because the eighteenth century been preserved within the Vatican Museum (figs. three. 36, three. 37). ¹⁰³ There are seven different niches on both sides of this oblong area of interest. the guts of every staff is occupied via a bigger semicircular area of interest. but the concept Santa Costanza is an unchanged treasure of Constantinian occasions shouldn't be permitted with out reservation and with no knowing tangle of difficulties encompass this monument and its interpretation. First there's the query of the mosaics, either these of the ambulatory famous by means of each customer to the construction and people of the higher a part of the drum which had deteriorated badly via the early 17th century once they have been got rid of. ¹⁰⁴ Even the mosaics within the vault of the ambulatory will not be accurately as they have been while initially put in. What we see is a nineteenth-century recovery conducted among 1836 and 1843. a detailed examine of the money owed of the paintings has proven that not more than 30 percentage of the unique floor used to be intact while the venture begun.