[18] Most of what is now known about the Carolingian church at St Denis resulted from a lengthy series of excavations begun under the American art historian Sumner McKnight Crosby in 1937.

[19] The structure altogether was about eighty meters long, with an imposing facade, a nave divided into three sections by two rows of marble columns, a transept, and apse and at the east end.

In his famous account of the work undertaken during his administration, Suger explained his decision to rebuild the church, due to the decrepit state of the old structure and its inability to cope with the crowds of pilgrims visiting the shrine of St Denis.

Suger began his rebuilding project at the western end of St Denis, demolishing the old Carolingian facade with its single, centrally located door.

This clear delineation of parts was to influence subsequent west façade designs as a common theme in the development of Gothic architecture and a marked departure from the Romanesque.

They clearly recorded Suger's patronage with the following inscription: On the lintel below the great tympanum showing the Last Judgement, beneath a carved figure of the kneeling Abbot, was inscribed the more modest plea; Receive, stern Judge, the prayers of your Suger, Let me be mercifully numbered among your sheep.Suger's western extension was completed in 1140 and the three new chapels in the narthex were consecrated on 9 June of that year, but the Romanesque nave between was yet unchanged.

"[22] Suger's great innovation in the new choir was the replacement of the heavy dividing walls in the apse and ambulatory with slender columns, so that the interior of that part of the church was filled with light.

He described "A circular string of chapels, by virtue of which the whole church would shine with the wonderful and uninterrupted light of most luminous windows, pervading the interior beauty.

[23] Suger's masons drew on elements which evolved or had been introduced to Romanesque architecture: the rib vault with pointed arches, and exterior buttresses which made it possible to have larger windows and to eliminate interior walls.

It was the first time that these features had all been drawn together; and the new style evolved radically from the previous Romanesque architecture by the lightness of the structure and the unusually large size of the stained glass windows.

His successor, who completed the western facade and upper storeys of the narthex, before going on to build the new choir, displayed a more restrained approach to decorative effects, relying on a simple repertoire of motifs, which may have proved more suitable for the lighter Gothic style that he helped to create.

Through the rule of the Angevin dynasty, the style was introduced to England and spread throughout France, the Low Countries, Germany, Spain, northern Italy and Sicily.

From the start it appears that Abbot Odo, with the approval of the Regent Blanche of Castile and her son, the young King Louis IX, planned for the new nave and its large crossing to have a much clearer focus as the French 'royal necropolis', or burial place.

That plan was fulfilled in 1264 under Abbot Matthew of Vendôme when the bones of 16 former kings and queens were relocated to new tombs arranged around the crossing, eight Carolingian monarchs to the south and eight Capetians to the north.

[33] These tombs, featuring lifelike carved recumbent effigies or gisants lying on raised bases, were badly damaged during the French revolution though all but two were subsequently restored by Viollet le Duc in 1860.

Solid masonry was replaced with vast window openings filled with brilliant stained glass (all destroyed in the Revolution) and interrupted only by the most slender of bar tracery—not only in the clerestory but also, perhaps for the first time, in the normally dark triforium level.

[39] In 1793, the National Convention, the revolutionary government, ordered the violation of the sepulchres and the destruction of the royal tombs, but agreed to create a commission to select those monuments which were of historical interest for preservation.

The jamb figures of the façade representing Old Testament royalty, mistakenly identified as images of royal French kings and queens, were removed from the portals and the tympana sculpture defaced.

[41][42] Debret resigned and was replaced by Eugène Viollet-le-Duc, who had the support of Prosper Mérimée, the French author who led campaign for the restoration of ruined Gothic architecture in France.

[43] In December 2016, 170 years after the north tower's dismantlement and following several false starts, the Ministry of Culture again proposed its reconstruction after concluding it was technically feasible—albeit without public funding.

As a result of the Rayonnant reconstruction in the triforium was given windows, and the upper walls were entirely filled with glass, which reached upward into the arches of the vaults, flooding the church with light.

[54] The apse with its two ambulatories and axial chapels was extensively rebuilt in the 12th century, to connect harmoniously with the new and larger nave, but a major effort was made to save the early Gothic features created by Suger, including the double disambulatory with its large windows.

To accomplish this, four large pillars were installed in the crypt to support the upper level, and the walls of the first traverse of the sanctuary were placed at an angle to connect with the wider transept.

[58] During the reign of Henry IV, the central portion of this crypt was devoted the Bourbon dynasty, but the tombs themselves were simple lead coffins in wood cases.

These included the tombs of Clovis I, Charles Martel, Constance of Castile, Pepin the Short, Robert the Pious and Hugh Capet (which disappeared during the Revolution).

[60] The monument to Henry II of France and Catherine de Medici (1559) followed a similar format; a Roman temple, in this case designed by the celebrated Renaissance architect Primatrice with sculpture on the roof depicting the King and Queen in prayer.

In 2004, the mummified heart of the Dauphin, the boy who would have been Louis XVII, verified to be authentic by DNA testing, was placed in a crystal vase and sealed into the wall of the crypt.

[62] The Sacristy, the room where the clergy traditionally donned their vestments, was transformed by the architect Jacques Cellerier in 1812 into a Neo-classical gallery of murals which depict scenes from the history of the cathedral.

A work added to the Sacristy is "Allegory of the Divine Word", a painting by Simon Vouet, which originally had been commissioned by Louis XIII for the retable of the Chateau of Saint-Germain-en-Laye.

The influential features of the new façade include the tall, thin statues of Old Testament prophets and kings attached to columns (jamb figures) flanking the portals (destroyed in 1771 but recorded in Montfaucon's drawings).