The church-fortress stands in the north of the spacious square. The three-aisled Romanesque pier basilica in the centre, with its 13th century slender west tower, forms the core of the entire ensemble. The church and the oval enclosing wall were altered at the end of 15th century. The church got a saddle roof set on the banked aisle walls and as such the tower was included in the roof. The enclosing wall wall was heightened and a three-tiered clerestory was attached to the inner wall; a wall-walk in the first upper storey provides access to the loopholes, the meurtrieres and the machicolation, as well as to the storerooms.