There have been religious buildings on the site since the 4th century AD, which were repeatedly destroyed and rebuilt during the Early Middle Ages.

The town of Saint-Quentin has been identified with the Roman city of Augusta Veromandurorum, a commercial center at an important crossroads.

It takes its present name from the Christian missionary Saint Caius Quintinus, who was beheaded there in 287 AD.

[1] Legend says the body was found many years later in the nearby marches of the River Somme by a Roman widow named Eusebia.

She reburied the remains at the top of the hill at the center of the present town and built a small shrine to the martyr.

Excavations round the crypt of the present church have indeed found traces of a building from this date.

[2] Some sources say the town became the seat of a bishopric around 365, but after barbarians destroyed it in 531 the bishop moved to Noyon.

Saint Eligius (c. 588–660), Bishop of Noyon and counselor to Dagobert I, Merovingian king of France, rediscovered the tomb in the 7th century "under the pavement of the basilica".

Archaeologists have found the remains of walls from the Carolingian period, when the location was a flourishing monastery and pilgrimage site.

[6] In 900 the bodies of Saint-Quentin and two other saints were placed in stone sarcophagi in a newly constructed crypt.

[7] In the 10th century the Herbertian counts of Vermandois, principally Adalbert I (Albert the Pious c. 915–987), replaced the monks with a congregation of secular canons.

[2] The canons of the collegiate chapter lived in separate houses within the church precincts, and most were not ordained priests.

That year Cardinal Robert of Courçon instituted a reform whereby ordained parish priests in nine parish churches would administer the sacraments, independent of the chapter, although they would pay the chapter a portion of their fees for baptisms, marriages and funerals.

Construction then continued westward from the apse towards the 12th-century tower, which eventually became the entrance to the collegiate church.

That year Nicolas de Roye, who was related to several of the canons, became the new bishop after Gérard's death.

[6][c] In 1417 Louis XI of France (1423–83) donated 1,000 gold crowns to completely rebuild the south arm of the small transept, which was at risk of collapsing.

During the French Revolution (1789–99) the building was damaged by Jacobins who converted it into a Temple of Reason, then a fodder store and a stable.

On 1 July 1916 an allied airplane dropped a bomb on the railway station, which ignited a wagon of explosives.

Great damage was done to the buildings of the city by the explosion, and seven of the large windows of the basilica were broken.

[3] When French forces recaptured Saint-Quentin on 1 October 1918 they arrested a German engineer who was preparing to blow up the severely damaged building.

As a first step about 3,000 cubic metres (110,000 cu ft) of cut stone and rubble were cleared by German prisoners of war.

Specialized workers undertook urgent reinforcements of masonry, and parts of damaged sculptures were stored for later restoration.

A temporary roof was built to protect the structure from weather, covered by fibro-cement and Ruberoid sheeting.

[6] The nave is built to a conventional 12th-century plan with three levels: arcades, triforium and high windows.

[6] The floor of the nave has an octagonal labyrinth of black and white paving stones from the late 15th century, 260 metres (850 ft) in length.

One wall of the nave has a half relief stone sculpture of the Tree of Jesse, the genealogy of Christ, from the 16th century.

[11] The south branch of the small transept was almost ruined in 1460, and was completely rebuilt by Colard Noël in Flamboyant Gothic style.

There is a statue of the apostle Quentin on the central turret, executed by Pierre Vaideau, one of the king's carpenters.