The present church dates from the late 14th century, but due to wars and the ruin of Montdidier in the 15th century, it took 100 years to build. The portal, designed by Chappion, is remarkable. From the first church, the Roman-Byzantine baptismal font (11th century) in black Tournai marble is particularly beautiful and curious. The relics of the town's patron saints, Lugle and Luglien, are preserved in a silver-plated bronze chase dating from 1839. A must-see is a superb 12th-century Romanesque Christ.