Blasimon Abbey, Romanesque abbey in Blasimon, France

Blasimon Abbey, north of the village between the RD127 and RD17, is a former Catholic abbey whose church, now Saint-Nicolas, has a rectangular plan of three nave bays plus a choir bay, all with ribbed vaults. The mid-12th-century west facade and first bay were rebuilt around 1150, and the north wall keeps a 13th-century square defence tower with a stair to the vaults. Of the monastic buildings only the 12th-century east cloister wing and the ruined chapter house remain.

Blasimon Abbey is first documented in 980, when its abbot gave a vineyard holding to the monastery of Squirs, later La Réole. The church was built between the 11th and 13th centuries, with the facade and western bay added around the mid-12th century and ribbed vaults in the 13th. Huguenots besieged the monastery in 1587, and the monks withdrew to the priory of Sauveterre until June 1622. From 1778 the abbey was officially dismantled and partly destroyed.

The abbey church, now Saint-Nicolas, keeps its original dedication to Saint Maurice. In the chapter house of the mid-12th century, pairs of engaged columns survive: those on the left were cut at mid-height when a bay was pierced later, while those on the right remain intact, their capitals wrapped in a pearled sheath that releases curled leaves at the corners.

The abbey stands north of the village on ground between the RD127 toward Mérignas and the RD17 toward Bossugan. The conventual buildings are ruins and only the eastern cloister wing survives, so the visit centres on the exterior of Saint-Nicolas church and the chapter house. The site is grassy and uneven in places.

The moats around the abbey were fed by the Gamage stream, but neglect turned the church's surroundings into marshland; in 1855 the parish priest, M. Monmaton, had the ditches filled in. The square Saint-Nicolas tower, pierced with arrow slits, was later converted into a dovecote.