Collegiata dei Santi Pietro e Orso

The Collegiate Church of Saints Peter and Orso, known as Sant'Orso, is an eleventh-century Romanesque basilica built over an early Christian burial site in Aosta.

Why it matters

Sant'Orso is one of Aosta's principal religious monuments and an important centre of Ottonian art. Archaeological excavations revealed a fourth- or fifth-century funerary building beneath the south nave, showing that this area was used for Christian burial from the earliest centuries of the faith in the valley.

What to notice

The basilica has three aisles and semicircular apses, with a crypt whose masonry predates the Romanesque church. The fifteenth-century wooden choir stalls, eleventh-century frescoes beneath the roof and a mosaic of Samson and the lion are among its notable features. The twelfth-century cloister preserves carved stonework.

Context and history

The site began as an extramural necropolis and formed part of an early Christian complex with San Lorenzo. A church was enlarged in the ninth century, and the Romanesque basilica took its present shape in the early eleventh century. The bell tower incorporates an earlier phase dating to 989 and later formed part of a defensive system. The collegiate chapter of Saints Peter and Orso shaped the religious life of medieval Aosta.