With a Latin cross floor plan, the church has a single nave with 4 rib-vaulted bays, a double rib-vaulted transept and a rib-vaulted 5-sided apse. The original church dates from the late 12th century, but was partly destroyed in 1433/1434. It then underwent a number of modifications:
- 1550: the church was enlarged by the addition of 2 aisles forming a transept on either side. The old choir became a crossing and the new choir was built to the east of the previous one.
- 1665: repair work on the choir.
- 1695: the nave is in danger of collapse.
- 1736 to 1739: the nave is summarily repaired with masonry (framework and roof).
- From 1832 to 1834, the bell tower's roof frame was rebuilt by removing the gable roof and replacing it with a dome topped by a spire. The north access door under the bell tower was rebuilt (1st May 1833).
- 1897: A flamboyant-style bay was opened in the north wall. The entrance door is replaced by a square opening and the bull's eye above it by an oven mouth.
- 1898: removal of the west entrance porch.
EGLISE SAINT-MARTIN DE SONCOURT-SUR-MARNE
