The Basilica di San Saturnino is the oldest surviving Christian building in Sardinia, its foundations dating to the late 4th or early 5th century. It stands outside the old city walls to the east, now incongruously located near a main road but enclosed in a pleasant walled garden. The building — a pale stone church of restrained but powerful form — has survived the centuries remarkably intact, given its age and the turbulent history of the city.
The interior is plain by any standard: rough stone walls, minimal decoration, the essential geometry of the early Christian basilica. This plainness reads differently from the stripped interiors of post-Reformation churches; here it reflects the simplicity of the earliest Christian architecture, before the accumulated wealth of the medieval church transformed the style. The adjacent garden has some Roman-period fragments and sarcophagi from the surrounding necropolis.