There must have been a first sanctuary at Louin before the year 1000, as a section of wall with a double string of bricks has survived in the presbytery garden. The name Louin itself appears in 1095. Possession of the Saint-Martin church was confirmed to the abbey of Airvault in 1113. The 1880 church has a Latin cross plan with a flat chevet. It is 34 m long and 8 m wide. The transept is over 19 m wide. In keeping with the Romanesque style, the brick vaults are round-arched, with brick double arches resting on unadorned canted pilasters projecting from the wall. The façade features three tall, narrow bays. The central bay is taller than the two side bays.