Several points of detail catch the eye immediately, especially one most unusual feature--that the axes of the barrelling are at right angles to the longitudinal axes of the church. One notices also the great height of the aisles, and the transfer of capitals from their usual position on the columns of the nave, to the vaulting shafts. The aisle columns are engaged in the wall. The apse has a fine ambulatory, and five square radiating chapels. This part of the church dates from the latter part of the eleventh century, and contrary to the evidence of the square chapels, which are somewhat Cistercian, was built under Clunisian influence. Roman example also is apparent. Over the transept is a fine central tower of the twelfth century, beneath which is a dome with Burgundian fluted pilasters. The general barbarity of the romanesque is lightened in the apse by carved shafts, of great delicacy and beauty, which have been selected by Viollet-le-Duc for illustrating the section on colonnettes in his "Dictionnaire Raisonné." The lower part of the narthex, or rather its extraordinarily massive pillars, are generally attributed to the tenth century; the towers, both of which have some good carving, to the eleventh; and the upper part of the south-west tower to the twelfth. The upper chamber of the narthex, loopholed in several places, was probably intended for the defence of the abbey,[131] further security being afforded by the enceinte and gate, of which the round tower opposite formed part. A door opened from the upper narthex to the interior of the church, so that defenders might attend the office. The crypt, which occupies the whole of the space beneath the choir, has many pillars, so cunningly disposed that they give to this part of the church an appearance of much greater size than is really the case. It contains several relics of the past, notably a wooden vierge of the twelfth century, the sarcophagus of St. Valérien, and a twelfth century fresco, the earliest of its kind in the department. The central chapel in the crypt is the best part of the building, architecturally; though the beautiful columns and capitals of the eleventh century, including two Roman ones, do not harmonize well with the primitive roof. Very little now remains of the ancient monastery; but the fifteenth-century salle abbatiale is still to be seen in the Place des Arts, on the south-east side of the church. The buildings on the site of the cloisters are still known as the carré. Saint Philibert, after whom the church is named, was not a Burgundian saint; but the monks who had the keeping of his relics, driven from their monastery of Noirmoutiers, established themselves at Tournus. That the cult of this Saint eventually gained great popularity in Burgundy, is evident from the number of churches--St. Philibert of Dijon, of Mersault, &c.--dedicated to him throughout the province.