The cathedral is particularly known for the great size and unity of its interior, the sculptural decoration of its portals, and the large collection of 13th century stained glass windows.

Beginning in about 1150 the Archbishop Pierre de La Châtre enlarged the old cathedral by adding two new collateral aisles, one on either side, each with two Romanesque portals, and also planned the reconstruction of the west front.

The sculptures on the portal above the far-right door depict scenes from the life of St Ursinus, a local saint and the first bishop of the diocese.

They include a depiction of Ursinus consecrating the cathedral (center) and the baptism of the Roman senator Leocadus and his son Ludre (top).

[13] The lower arcade contain a collection of sixty four bas-relief sculptures depicting examples of divine intervention drawn from commentaries on the Bible in the Talmud.

They were carved in the thirteenth century and their unique iconography was possibly designed by a member of Bourges's large Jewish community.

[13][14] The spandrels between these niches feature an extended Genesis cycle which would originally have told the story from the beginning of Creation to God's Covenant with Noah.

It was given an elaborate Flamboyant Gothic decoration including a profusion of ornamental pinnacles and crockets, as well as copies of 13th-century statues installed in the niches.

The upper room of the buttress was used as the office of the architect, and has plans of the bays and a rose window etched on the stone floor, where they could be consulted by cathedral builders.

[18] Unlike most other High Gothic cathedrals, Bourges does not have a transept, but there is a porch and portal on the south side which originally was used only by the clergy.

It contains vestiges of the older Romanesque church, particularly six column-statues which date to about 1150–60, which were put in place under the porch in the 13th century as a reminder of the long history of the cathedral.

Some of the sculpture is inscribed with the heart and letter J emblem of the family of Jacques Coeur, prominent Bourges merchants and major donors to the cathedral.

Bourges Cathedral is notable for the simplicity of its plan, which did without transepts but which adopted the double-aisled design found in earlier churches such as the Early-Christian basilica of St Peter's in Rome or in Notre Dame de Paris.

Each pillar is composed of a central column, two of which are attached to the slender colonettes which spread out at the top and connect to the rib vaults.

[24] In the Middle Ages, the choir was used exclusively by the clergy and was separated from the nave by a decorated rood screen or ornamental barrier.

At the top level, the high windows with their circular oculi are fit into the peaks of the arches, adding to the sensation of uninterrupted height.

These changes included new carved choir stalls made by René-Michel Slodtz, marble pavement in a checkerboard pattern, and a new main altar designed by Louis Vassé, formally consecrated in 1767.

[24] The cathedral is ringed with chapels constructed over the centuries, inserted into the spaces between the buttresses on the flanks, and radiating in a half-circle around the chevet.

[24] The Chapel of Saint Anne, on the south side of the disambulatory, was donated by one of the wealthy members of the Chapter, Pierre Tullier.

The family was forced to sell his residence and his burial rights in the chapel to another wealthy noble, Charles de L'Aubespine.

[26] Fine examples of 15th-century sculpture are found in the Chapel of Notre-Dame La Blanche, in the centre of the apse at the east end of the cathedral.

Its arched ceiling is supported by massive pillars and seven arcades, and a wall three metres thick pierced with lancet windows.

At one time it apparently served as the master builder's office; the plans of the rose window on the west pignon are etched onto the floor.

[27] Today it has a collection of stained glass made between 1391 and 1397 which formerly was installed in the windows of the Sainte-Chapelle chapel constructed by John, Duke of Berry, which was destroyed in 1757.

The Duke was an important art collector of the era; among the works he commissioned was the Très Riches Heures du Duc de Berry.

[27] Other objects of interest in the lower church include pieces of sculpture the original Jubé, or Rood screen, made in Paris in the 1230s, which divided the choir from the nave until the 18th century.

The famous windows at Bourges are mostly on the ground level, giving a better opportunity than most Gothic cathedrals offer to examine them closely.

Other windows show the Passion and three of Christ's parables; the Good Samaritan, the Prodigal Son and the story of Dives and Lazarus.

The French art historian Louis Grodecki identified three distinct masters or workshops involved in the glazing, one of whom may also have worked on the windows of Poitiers Cathedral.

[33] Nearly all of the upper windows of the nave and the collateral aisle are filled with grayish grisaille glass, to provide maximum light.