Église Saint-Omer de Lillers, Romanesque church in Lillers, France

The Église Saint-Omer de Lillers is a Romanesque church built in the first half of the 12th century. It has a Latin cross plan with two high side aisles, three chapels, and an ambulatory behind the choir. A square central tower rises above the crossing, and the west facade shows a portal topped by two twin windows, a blind row of nine columns under a stone rose, and a gable with a carved round stone. The walls are of light grey and beige stone blocks, with darker patchy masonry on the corner section; tall buttresses divide the side wall, and the side aisle is roofed in dark slate.

Built between 1125 and 1135 by Lord Wenemar of Lillers following his pilgrimage to Rome, the church rests on 11th-century foundations. The patron brought back architectural ideas from the south that shaped the building's design.

The choir features carved capitals and 18th-century wooden furnishings, while stained glass windows show religious figures and scenes throughout the interior. These decorative elements shape how visitors experience the space today.

The church is open to the public for the Journées du Patrimoine heritage days; Sunday Mass is celebrated twice a month under the Diocese of Arras. The west facade, which collapsed in 1971, has been rebuilt, so the entrance front differs from the medieval nave behind it.

The 12th-century crucifix of the Christ of the Holy Blood at the back of the choir, crowned with joined feet and oversized limbs, was the object of a pilgrimage miracle. The west facade collapsed in 1971 and was rebuilt; the funeral of Lola Daviet was held here on 24 October 2022.