Arch of Augustus in Aosta: A Roman Monument Marking the City’s Foundation
Visitor Information
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Country: Italy
Civilization: Roman
Remains: Civic
History
The Arch of Augustus of Aosta, Italy, was erected in 25 BC to celebrate the Roman conquest of the Salassi tribe, a local people who inhabited the region before Roman control. This victory was led by the Roman general Aulus Terentius Varro Murena, who established a military camp on the site that later became the Roman colony Augusta Praetoria, the foundation of modern Aosta.
In Roman times, the arch stood at the eastern entrance of the city, near the Porta Praetoria, and was aligned with the decumanus maximus, the main east-west street of the settlement. This positioning emphasized its role as a grand gateway marking the city’s foundation and Roman authority.
During the Middle Ages, the arch acquired a religious significance and was known as the Saint-Voût, or “Holy Arch,” because an image of Jesus was placed there. In the 12th century, the arch’s interior was adapted for residential use by a local noble family. Later, in 1318, a small fortification was constructed inside the arch to house crossbowmen, reflecting its strategic military use during this period.
In 1449, a wooden crucifix was installed within the arch as a votive offering intended to protect the city from flooding caused by the nearby Buthier river. The original crucifix from this time is now preserved in the Museum of Aosta Cathedral’s Treasures. By the early 18th century, the arch’s original attic, which once crowned the structure, was removed and replaced with a slate roof to prevent damage from water infiltration.
The arch underwent restoration and structural consolidation in 1912 under the direction of Ernesto Schiaparelli. During these works, excavations uncovered two gilded bronze letters believed to be part of the original inscription that once adorned the attic, providing further insight into the monument’s Roman origins.
Remains
The Arch of Augustus is a single-vaulted triumphal arch constructed from large blocks of conglomerate stone. Its main feature is a barrel vault, a semicircular arch that spans the width of the monument, creating a passageway beneath. The arch rises to a height of 11.4 meters at the keystone, the central stone at the top of the arch that locks the structure in place.
The exterior of the arch is decorated with ten engaged columns, which are columns partially embedded in the wall. These columns are topped with Corinthian capitals, a style characterized by ornate acanthus leaves. Above the columns, the entablature, the horizontal structure supported by the columns, displays elements of the Doric order, including metopes (square panels) and triglyphs (three vertical grooves), combining two classical architectural styles.
Originally, the arch was crowned by an attic, a raised section above the entablature that likely bore inscriptions or decorative elements. This attic was removed in the early 18th century and replaced with a flat slate roof to protect the monument from water damage.
Beneath the vault, a wooden crucifix is displayed, serving as a replica of the original crucifix installed in 1449 as a protective symbol against flooding. The original crucifix is now housed in the nearby museum.
