Cornouvaille, was installed in 1550. In 1567, during the Wars of Religion, Protestant bands pillaged the city, and caused considerable damage to the cathedral. The damage was largely repaired by 1576 under Bishop Jacques Amyot. In 1764 the very ornate Gothic rood screen, or choir grill, put in place under King Francois I of France, was destroyed, in keeping with a new Vatican anti-Reformation doctrine to make the interior more appealing to ordinary churchgoers. It was replaced by a lacelike iron grill made by the Paris iron craftsman Dhumier, with gates by sculptor Sébastien Slodtz to a design by Claude-Nicolas Ledoux. Exterior The narrative sculptural program of the portals on the west end are noted for their extent and variety. The stimulus was provided about 1270 by Jean de Châlons-Rochefort, who had recently become Count of Auxerre, having supported the Duke of Burgundy against his own brother, by marrying Alix, the heiress of Auxerre. He was the largest fief-holder in the duchy and commemorated the new status of his fief of Auxerre by enriching the front of its chief ornament, the cathedral, whose Carolingian nave had been erected by his ancestor Hugh de Châlons, 10th-century bishop of Auxerre. Its program of sculpture was carried through long after his death and completed in the early 15th century. North Tower The construction of the north tower began in about 1250, and reached the completion of the portal at its base, but then practically ceased for nearly two centuries. The work did not resume the beginning of the 16th century. The upper portions were built largely in the ornate flamboyant Gothic style, and were completed in about 1543. The tower contains the belfry of the cathedral, within the fifth, or top level. It is approximately the same height as the towers of Notre-Dame de Paris. The three levels above the portal are decorated with niches covered by gables. The roof has a small terrace surrounded by a balustrade. The tower is given a more graceful silhouette by the prolongation of the buttresses at the angles. The buttresses are also ornamented and prolonged by slender spires. On the northeast side of the tower is attached a slender octagonal tower with narrow windows, which serves as a stairway from the base of the tower to the summit. At the top it has its own Renaissance-style belfry and a lantern, adorned with a cross marking the