Basilica of Santa Sabina site features

From outside it gives almost nothing away. Santa Sabina is a long plain brick box on a ridge, with a tiled roof, a row of tall windows high in its flank and no facade worth the name — no columns, no statues, no marble front. You go in through a courtyard and a covered porch.

The porch is where the important thing is. Set in the wall is a pair of dark cypress doors, the timber gone almost black with age, each leaf divided into a grid of rectangular panels — eighteen of them survive — with shallow carved scenes inside the frames: figures a hand's breadth high, crowded, worn smooth at the edges where people have brushed past for sixteen centuries. Nothing labels them, including the panel near the top left showing three figures with their arms out in front of a line of gabled buildings, which is the oldest crucifixion anybody put on public display. You have to go looking for it.

Inside, the room is long, high, white and almost empty, and the surprise is how much of it is simply air. Twenty-four fluted columns in two rows run the length of the nave, carrying round arches, their capitals and bases matching one another exactly. There are no side chapels cut into the walls to break the rhythm, and almost no colour: the decoration is the colonnade and the proportion.

The light is the other half of it, and it does not look like church light. The high windows are filled not with glass but with panels of translucent stone, so what comes in is flat, milky and shadowless, more like an overcast sky indoors than a sunbeam. The one piece of colour is above the door as you turn to leave: a long band of gold lettering on a deep blue ground, an inscription in Latin running the width of the wall.

The cypress doors

In the porch, generally agreed to be original and of about 430-432, with eighteen surviving panels of scenes from both testaments. One panel is the first known publicly displayed image of the crucifixion of Christ, showing Jesus and two other figures before architecture recalling a Roman mausoleum.

The twenty-four columns

Fluted Corinthian marble, reused from the Temple of Juno, capitals and bases matched, dividing the church into three naves.

The selenite windows

Clerestory windows of selenite rather than glass, preserving the original fifth-century light.

The dedication inscription

The original fifth-century mosaic frieze above the doorway inside: Latin hexameters in gold letters on an azure ground.

The bell tower and cloister

Built after the Dominicans arrived, for the community established around Saint Dominic.