Despite being called a
basilica, Saint-Sernin's deviates from the basilica plan of early Christian architecture in a few ways. It is much larger compared to earlier churches, measuring 104m in length. It is also constructed mostly of brick. The building is in the form of a crucifix. The ceilings are
vaulted, unlike many of the earlier churches. Saint-Sernin's contains radiating chapels which were used to display important relics. Another deviation from the earlier Christian churches is the addition of an
ambulatory, a walkway that goes around the nave and side aisles to allow for viewing of the radiating chapels (which could be done while mass was being held without interrupting the ceremony). For these and other reasons, Saint-Sernin's is often said to follow the "pilgrimage plan" instead of the traditional basilica plan.
Exterior On the exterior, the
bell tower, standing directly over the
transept crossing, is the most visible feature. It is divided into five tiers, of which the lower three, with Romanesque arches, date from the 12th century and the upper two from the 13th century (circa 1270). The
spire was added in the 15th century. The bell tower is slightly inclined towards the west direction, which is why from certain standpoints the bell tower roof, whose axis is perpendicular to the ground, appears to be inclined to the tower itself. The
chevet is the oldest part of the building, constructed in the 11th century, and consists of nine chapels, five opening from the
apse and four in the transepts. The exterior is additionally known for two doorways, the
Porte des Comtes and the
Porte Miègeville. Above the
Porte des Comtes is a depiction of
Lazarus and Dives. Dives in
hell can be seen above the central column. The doorway gets its name from a nearby
alcove in which the remains of four
Counts of Toulouse are kept. The
Porte Miègeville is known for its elaborate sculpture above the entrance: the ascending Christ, surrounded by superb angels, is the central figure on one of the oldest and most beautiful tympanums in
Romanesque architecture (end of 11th c. or circa 1115). Porte_Miégeville_-_Basilique_Saint-Sernin.jpg|Porte Miègeville Tympan - Porte Miégeville - Basilique Saint-Sernin.jpg|Tympanum of the Porte Miègeville St% 20sernin% 20(3)(1).jpg|Saint Peter St% 20sernin% 20(6)(1).jpg|Saint James the Great Console aux personnages symmétiques.JPG|Two shepherds slaying lions Console au roi David.JPG|King David playing the rebec Basilica_Saint-Sernin_-_Simon_Magus.jpg|Simon the magician, the demons and the birth of the vine Capital_of_the_massacre_of_innocents_-_Porte_Miègeville_-_Basilique_Saint-Sernin.jpg|The Massacre of the Holy Innocents Capital_of_Annunciation_and_Visitation_-_Porte_Miègeville_-_Basilique_Saint-Sernin.jpg|The Annunciation and Visitation of the Virgin Mary Capital_of_Original_sin_-_Porte_Miègeville_-_Basilique_Saint-Sernin.jpg|Adam and Eve being chased out of the Garden of Eden
Interior The interior of the basilica measures 115 x 64 x 21 meters, making it vast for a Romanesque church. The central
nave is
barrel vaulted; the four
aisles have
rib vaults and are supported by
buttresses. Directly under the tower and the transept is a marble altar, consecrated by
Pope Urban II in 1096 and designed by
Bernard Gelduin. As well as
Saint Saturnin,
Saint Honoratus is also buried here. The crypt contains the relics of many other saints, including, by tradition, the Apostles St Simon and St Jude. The basilica also contains a large three-
manual Cavaillé-Coll organ built in 1888. Together with the Cavaillé-Coll instruments at
Saint-Sulpice and the
Church of St. Ouen, Rouen, it is considered to be one of the most important organs in France. It was inaugurated on 3 April 1889 by
Alexandre Guilmant. From 1992 to 1996, it was restored by organ builders
Jean-Loup Boisseau,
Bertrand Cattiaux and Patrice Bellet. The current Titular
organist is
Michel Bouvard.