[anc. Augusta Praetoria]
City situated at the confluence of two ancient Alpine passes, the Great and Little St Bernard, in Piedmont, Italy. The medieval nucleus lies within the Roman walls and important monuments of both periods survive. Founded as a Roman camp in 24 bc, and later colonized under Emperor Augustus (22 bc), it soon also became a Christian bishopric. In 1025 the city was in the possession of Umberto Biancamano, the feudal lord under Rudolf, King of Burgundy, and founder of the ruling family of Savoy. It was the birthplace of St Anselm (c. 1033/4–1109), who became Archbishop of Canterbury in 1093.
Of the Roman remains, the Porta Praetoria, the theatre, bridge and Arch of Augustus are best preserved and bear testimony to Aosta’s importance as a Roman Imperial city; there are also ruins of the Roman forum. From the period of St Anselm, two important monuments survive: the cathedral, dedicated to St John the Baptist, and the Benedictine abbey of S Orso, the latter with important 11th-century frescoes and 12th-century cloister capitals. The 12th-century mosaic pavement in the cathedral represents the ...