The name of SENS , the northernmost town in Burgundy, commemorates the Senones , the Gallic tribe whose shaggy troops all but captured Rome in 390 BC; they were only thwarted by the Capitoline geese cackling the garrison awake. Its heyday as a major ecclesiastical centre was in the twelfth and thirteenth centuries, but it lost its pre-eminence in the ensuing centuries largely through damage caused by the Hundred Years War and the Wars of Religion. Nowadays, it is a quiet and unexciting place on the banks of the River Yonne, although the cathedral, its treasury and the adjacent museum make a stop worthwhile. Contained within a ring of tree-lined boulevards where the city walls once stood, the town's ancient centre is still dominated by the Cathédrale St-Étienne , close to the intersection of Grande-Rue and rue de la République, which, together with their prolongations, neatly quarter the town centre. Begun around 1130, it was the first of the great French Gothic cathedrals. Though an early example, the Gothic elements of airiness, space and weightlessness are fully realized in the height of the nave, the arcading of the aisles and the great rose window. The architect who completed it, William of Sens, was later to rebuild the choir of Canterbury Cathedral in England - the link being Thomas à Becket, who had previously spent several years in exile around Sens. The story of his murder is told in the twelfth-century windows in the north aisle of the choir, just part of the cathedral's outstanding collection of stained glass. The treasury , which can be entered either from the cathedral or the museum , is also uncommonly rich, containing Islamic, Byzantine and French vestments, jewels and embroideries. Next door is the thirteenth-century Palais Synodal , with its roof of Burgundian glazed tiles restored by the nineteenth-century "purist" Viollet-le-Duc, as were those of so many other buildings in this region. Its vaulted halls, originally designed to accommodate the ecclesiastical courts, now house the excellent Musée de Sens (July & Aug daily 10am-6pm; Sept-June Mon, Thurs & Fri 2-6pm, Wed, Sat & Sun 10am-6pm; 20F/?3.05, free Wed), which makes all possible use of available space to display a prize collection of exhibits found in the region, including statuary from the cathedral and Gallo-Roman mosaics. Prize exhibits include the Villethierry treasure, which consists of 867 items of bronze jewellery in a jar, and is thought to be a jeweller's hoard; a collection of bone combs; and the facade of Sens' second-century public baths. The vaults of the building - partly constituting the remains of a Gallo-Roman building, including baths heated through the pavement - have also been incorporated into the museum, along with displays of Gallo-Roman metalwork, jewellery and textile crafts, many of which were discovered when the basement was excavated. Facing the cathedral across place de la République are fine wood and iron halles , where a market is held on Monday, Friday and Saturday mornings. The square stands right in the centre of town and is intersected by the two main streets, rue de la République and Grande-Rue . These streets are lined with old houses now converted into shops, and are mainly reserved for pedestrians. There are two particularly finely carved and timbered houses on the corner of rue Jean-Cousin one block south of the square: the Maison d'Abraham and the Maison du Pilier , with Maison Jean Cousin on rue du Général-Alix.