discovered. Outside the town walls is the Arch of Augustus, a triumphal arch in honour of Augustus, built in 35 BC to celebrate the victory of consul Varro Murena over the Salassi. About to the west is a single-arched Roman bridge, called the Pont d'Aël. It has a closed passage, lighted by windows for foot passengers in winter, and above it an open footpath. There are considerable remains of the ancient road from Eporedia (modern Ivrea) to Augusta Praetoria into the Aosta Valley. The modern railway follows this route, notable for the Pont Saint-Martin, which has a single arch with a span of and a roadway wide; the cutting of Donnas; and the Roman bridges of Cillian (Saint-Vincent) and Aosta (Pont de Pierre). Other sights The Cathedral, built in the 4th century and replaced in the 11th century by a new edifice dedicated to the Madonna. It is annexed to the Roman Forum. The Romanesque-Gothic Collegiate church of Saint Ursus (Saint-Ours). Its most evocative feature is the cloister, which can be entered through a hall on the left of the façade. It is dedicated to Ursus of Aosta. The Saint-Bénin College, built about 1000 by the Benedictines. It is now an exhibition site. The Bridge of Grand Arvou, a medieval arch bridge-aqueduct. Transport Aosta lies on the crossroad of two major trans-alpine trunk roads: national road 26 (Italian: SS26, French: RN26) connecting the city of Chivasso to Little St Bernard Pass on the Italy-France border, and national road 27 (Italian: SS27, French: RN27) connecting the city of Aosta to the Great St Bernard Pass on the Italy-Switzerland border. Aosta is also served by the A5 motorway between Turin and Courmayeur. Aosta railway station, opened in 1886, forms part of the Chivasso–Ivrea–Aosta railway. Direct trains only connect Aosta up to the city of Ivrea. The branch line to nearby Pré-Saint-Didier, in the Valdigne, on the way towards Courmayeur was closed in 2015. Train service is operated by Trenitalia. The main bus hub is located near the Aosta train station. Buses connect the city of Aosta to the nearby valleys and to destinations outside the region, including Turin, Milan, Chamonix (France) and Martigny (Switzerland). Aosta airport is located 5 km to the east of the city. Notable people List of mayors of Aosta Anselm of Canterbury (1033–1109), archbishop of Canterbury from 1093 to 1109. Xavier de Maistre (1763–1852), writer of Le lépreux