The church of Santo Stefano is located in the Northern zone of the city of Aosta, just outside the walled perimeter of Augusta Praetoria near the ancient Roman road which, exiting from Porta Principalis Sinistra, led to the Alpis Poenina (the current Gran San Bernardo pass).

The first documental information on the parish of Saint Stephan dates back to the 13th century. In other medieval documents the building of worship was indicated as a “Basilica”, perhaps due to its particular position inside a funeral area from a previous era.

During the middle ages however, the church was a meeting point within a micro-urban reality such as the area of Aosta called “II Faubourg de Saint Etienne” or “De La Rive”, from the name of the canal that still crosses it today.

Up until 1776, like other similar areas, this suburb represented a veritable urban-administrative entity, separate from the rest of the city of Aosta.
The current building was built on the walled structures of a previous church from the 15th century, to which an inscription on the architrave of the right hand entrance door refers: “Hoc opus fecit fieri Jaquemin Pastor” (Jaquemin Pastor had this building built). The church was restored extensively in 1728-29, as appears from the agreement stipulated on 25 April 1728 by the parish priest Clérin, who also had the bell tower raised. The frescoes on the facade were, on the other hand, painted by his successor Michel-Joseph Rosaire, the parish priest between 1729 and 1735.