Roman bridge at Pont-Saint-Martin

Access

After 150m from the motorway junction exit at Pont-Saint-Martin, turn right and take the second exit at the first roundabout. A little further on at the second roundabout: take the third exit, and enter the town of Pont-Saint-Martin. After a few hundred metres, turn right onto for the Valle del Lys. Continue through the village of Pont-Saint-Martin for another 500 metres before turning right off the regional road. Continue straight on for about a hundred metres, cross the Lys in front of the Roman bridge and leave your car in the car park  🅿️ in Piazza IV Novembre, which has some spaces with a 60-minute disc zone and the remainder in a blue zone. There are other free car parks nearby.

[0h03'] - [1.4km]
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Pont-Saint-Martin can also be reached by bus 🚌 with the company Vita Group, with the Aosta - Pont-Saint-Martin line: stop at the point of departure and by train 🚊, with Trenitalia, line Turin - Aosta.

The information provided has been carefully checked on the date of the route survey. However, you are strongly advised to check any changes that may have occurred since then, especially regarding the route to the point of departure. Before embarking on your journey, it is advisable to consult up-to-date navigation tools for accurate and up-to-date directions. We recommend the use of satellite navigation apps, such as Google Maps or Apple Maps, to ensure the most accurate and safe route.

Introduction

With its imposing structure, the Pont Saint-Martin is not just a link between the banks of a river, but a symbol of the Aosta Valley's thousand-year history and the excellence of Roman engineering, capable of withstanding time while maintaining its beauty and functionality intact to this day.

Description

The Pont Saint-Martin, known in Valle d'Aosta patois as Pon Sèn Marteun and in Walser language as Martinstäg, is one of the most fascinating examples of Roman engineering still visible in Valle d'Aosta. This stone low arch bridge stands majestically in the town of the same name, a short distance from the confluence of the Lys and the Dora Baltea. Built in the first decades of the 1st century BC, during the empire of Octavian Augustus, the bridge has a single span of 36 metres (or, according to other sources, 31.4 metres), making it one of the largest and boldest bridges of antiquity, capable of supporting the passage of travellers for over two thousand years.

Viability and Dating of the Pont Saint-Martin

The bridge is part of the network of the Roman road of Gaul, a fundamental artery that connected Italy to Gaul via Augusta Praetoria Salassorum (today's Aosta). From here, the road forked towards the Great and Little St Bernard Passes, crucial junctions for Roman control and expansion in the Alps. The present structure probably dates back to the Augustan period, when it was necessary to consolidate and modernise the local road system to facilitate connections with the new Roman colonies. Some studies speculate that the present bridge replaced an older crossing, dating back to 141 or 120 BC, which was no longer suitable for heavy traffic due to less developed construction techniques.

Structure and Construction Techniques

The Pont Saint-Martin stands out for its innovative technical features compared to typical Roman bridges. Its exceptionally wide span and slender arch with an almost segmented profile represent an important innovation, probably inspired by the nearby Aosta bridge, also built under Augustus and featuring a similar structure. With a span-to-arrow ratio of approximately 3.3 to 1, the arch of the Pont Saint-Martin deviates from the classical semicircular arches, providing stability and strength. The structure required massive piers to balance the lateral thrusts, thus allowing the material used in the vault to be reduced.

A unique element of the bridge is its 71 load-bearing wedges. These elements, with a vault thickness ratio of 1/34 of the span (a figure unsurpassed among the Roman bridges examined by engineer Colin O'Connor), constitute one of the most daring architectural innovations of the period. This ratio, lower than the usual Roman standards, demonstrates the Roman architects' skill in adapting construction techniques to the specificities of the site.

The Roman Bridge Museum

Nearby the bridge, in Piazza IV Novembre, there is a small museum dedicated to this extraordinary work of engineering. The layout allows visitors to explore technical, historical and archaeological details concerning the Pont Saint-Martin and the Roman road system in the Aosta Valley. Located in an exhibition hall accessible by a staircase, the museum is an opportunity to learn more about the history of the area and the central role the bridge has played over the centuries.