For St. Denis' abbey a Merovingian church had been built by Dagobert. Pépin and Charlemagne replaced it by a Carolingian church. By the XII century the abbatial had become inadequate for the pilgrim crowds; people were crushed to death on festival days, and Abbot Suger decided to rebuild. He began by demolishing a heavy vestibule which Charlemagne had put up as a kind of tomb over his father's grave, for Pépin had begged to be buried face downward in penance, before the abbey church. Suger replaced that encumbering porch by what is to-day a narthex, or forechurch, formed by the two westernmost bays of the edifice. In the thirties of the XI century he started the new works. Romanesque feeling lingered in the sculpture, and the stout vault ribs crossed each other in round arches. By 1140 the west façade was finished and ceremoniously consecrated. A month later, a still greater gathering met at St. Denis for the laying of the corner stone of the choir. To the sound of trumpets, Louis VII descended into the trench prepared for the foundation, and placed the first stone, and as the choir chanted of the jeweled walls of the heavenly city, _Lapides pretiosi omnes muri tui_, the king, profoundly moved, took from his finger a costly ring and threw it into the mortar, which had been mixed with holy water. Each baron and bishop, as he laid down a stone, did the same. Their vehement faith would turn to literal meaning the Psalmist's dream of the celestial city. In his choir, Suger united definitely the pointed arch with the intersecting ribs, and the ribs, now, were not the heavy ones used in his forechurch. All the arches at their crown were brought to the same height by a combination of stilting, pointing, or depressing them. In the outer aisle of his ambulatory, Suger introduced a fifth rib in each vault section, which welded the apse chapels with the procession path. For his inner aisle he employed what is called the broken-rib vault. First, the keystone was planted in the center and from it branched the four ribs, each regardless of making a straight diagonal. This became the generally accepted method for vaulting an ambulatory. Every part of his edifice Suger supervised with untiring energy. Owing to the waste of forest trees for machines of war, none of sufficient girth could be found for the outer roof covering. Suger lay brooding over this one night, then started up impetuously before dawn, took the measurements of the beams needed, and himself went into the dense forest. Before nine that morning he had found a giant tree; by noon ten others, and the timber was hauled in triumph to the abbey.