[2] The plan of the church today is the result of several major construction campaigns that began at the end of the twelfth century and concluded in the early sixteenth.

The nave columns appear distantly related to Notre-Dame de Paris but closer prototypes can be found in the hemicycle of Rouen Cathedral.

The church of Notre-Dame de Louviers underwent a dramatic expansion project during the Late Middle Ages.

The expansion of the nave necessitated the reworking of the upper parts of the church, which received a glazed triforium (later filled with cement) and a modified system of flying buttresses.

The amount of usable interior space increased dramatically as a result of these extensive expansion projects, which were funded in large part by Louviers' cloth guilds and elite patrons, including Guillaume II le Roux, Duke of Bourgtheroulde.

A great deal of the late medieval stained glass has been lost over time; however, several excellent examples remain intact.

Hoisting their blazons, weavers, stretchers, wool workers, and tanners accompany a bishop during a religious procession through the town of Louviers.

The sculptures themselves, however, are probably from the early 16th century, and can be linked to the artistic patronage of Georges d'Amboise at château de Gaillon.

The only construction that occurred in the early fifteenth century was the addition of the "Challenge Tower" to the church of Notre-Dame de Louviers.

[3] Because it faces a narrow street and is less ostentatious than its southern counterpart, the north facade has not received as much attention from restorers.

Overall, this expansion is harmonious, refined, and simple—adjectives that do not necessarily describe the modifications made to the exterior of the southern half of the church.

Stylistically, the projecting porch and façade created a visual link between Louviers and Rouen, home to very similar Late Gothic monuments and the seat of the powerful archbishop.

A veritable lacework of intricately carved stone, the completion of the façade and south porch in 1510 effectively reoriented the entire church.

"[3] Sinuous Flamboyant window tracery, tall ogee gables, an openwork balustrade, spiky pinnacles, and countless sculptures nestled in richly-carved nodding niches give the façade an unmatched quality of richness, visual complexity, and dynamism that was never replicated.