Sant'Agnese fuori le Mura and the Mausoleum of Santa Costanza

Church · Nomentano (Via Nomentana 349)Rome,Italy

A round fourth-century Rome mausoleum whose vault still carries the oldest Christian mosaics in place, beside a basilica over a martyr's grave.

The Mausoleum of Santa Costanza is a round brick tomb whose ring vault still carries its original fourth-century mosaic. It shows men treading grapes, carts bringing in the harvest, birds, branches, jugs and geometric panels — what a rich Roman house of the time would have had on its walls. These are the oldest Christian mosaics surviving in place in Rome. It was built between about 340 and 345 for a daughter of Constantine. A hundred and thirty metres away stands the basilica of Sant'Agnese, built in the 620s over the grave of a girl executed in the persecutions. You reach it down a long staircase lined with early Christian inscriptions, cut in the seventh century to bring pilgrims to the church, which stands at the level of the cemetery it was built over. The apse mosaic shows Agnes standing in gold with flames at her feet, and the catacomb galleries run under the floor. Neither building is easy to find open, which is why almost nobody sees them.

Worth knowing

Good to know

Morning or not at all — both buildings shut for several hours in the middle of the day, and the round mausoleum is often locked on Saturday afternoons for weddings.
These are two separate buildings a few minutes apart — the round mausoleum with the mosaics stands away from the basilica, and people regularly see one and leave without the other.
Notice that nothing in the harvest scenes is Christian — there is no cross, no saint and no Bible story, because Christian art had not yet developed images of its own.

Things to do

1
Walk the full ring under the mosaic
Enter the round building and take the outer walkway all the way round without stopping, looking up. Then do it again slowly. Each section of the vault carries a different pattern: vines with figures, scattered birds and vessels, then bands of pure geometry. The mosaics were laid in the fourth century, before anyone had settled what a Christian building should look like.
2
Read the gravestones on the way down
The way into the basilica is a long straight staircase running down under a barrel vault, with fragments of early Christian gravestones set into the walls on both sides. Read a few as you descend: names, ages, doves, an anchor. The stairs end at the church floor, which lies at the level of the old burial ground the basilica was built over.
3
Find Saint Agnes in the gold mosaic
The mosaic in the half-dome dates from the seventh century and is deliberately plain: a girl standing alone on a gold background in imperial dress, with a sword at her feet and flames on either side. A pope stands on each side of her, each holding a model of a building. The mausoleum's vault is covered in harvest scenes and birds, while here there is one saint on bare gold, made to be looked at as a holy figure rather than as decoration.