The semi-cylindrical abutments are among the oldest of mediæval buttresses. They are crowned with cones or capitals, the greater part of which are devoid of decoration.
Between its two towers, this gabled façade, the recesses and blind arcading of which form almost its sole decoration, is in strong contrast with the principal façade of the Cathedral. At once elegant and severe, like most of the monastic buildings of the 12th century, it lacks unity. All that part situated above the five windows of the first storey, including the rose-window, has been rebuilt in modern times. The very simple rose-window, between two lines of superimposed arcading, is protected, in the Champagne style, by a relieving-arch. The northern tower (_on the left_) was almost entirely rebuilt in the 19th century, on the lines of the old one. The simpler southern tower (_on the right_), with its arched windows and loopholes, is Roman of the 11th or 12th century. The pointed part of the façade is late 12th century, and dates from the time of the restorations by Pierre de Celle.
Three doors open on the nave. The central one is flanked by two columns with statues of St. Peter and St. Remi. The marble and granite columns came, no doubt, from some neighbouring Gallo-Roman building. These statues, with arms pressed close to their sides in the ancient stiff manner, are probably from the original basilicas.
Here, the architecture is peculiar. Pierced columns form a gallery connecting the upper courses. The galleries of the first storey are supported by two great columnar shafts, each formed of two portions joined by a stone ring and surmounted by bell-shaped marble capitals. The columns and capitals are Gallo-Roman.
[Illustration: THE NAVE (_seen from the Choir_) (_Cliché LL._)]
Alterations were made at different times to the nave which, in the 11th century, had a timber-work roof. Pierre de Celle lengthened it by two bays, the pointed arches of which contrast with the circular ones of the lower bays, and also increased its height. _Note the ogives above the round arches._ The visible timber-work was replaced with vaulting on diagonal ribs sustained by clusters of small Gothic columns backing up against the Roman piers, the latter being still visible. These heavy piers (composed of fourteen small columns) which surround the central nave, and whose capitals (_photo, p. 108_), with Barbaric wreathed astragals and foliage, recall the Carolingian period, contrast strikingly with the lightness of the apse. They are undoubtedly 11th century. All the stone vaulting of the nave, as far as the transept, was replaced after 1839 with wood and plaster, which collapsed under the bombardments of 1918, when the roof was burnt.