Located in Thimerais, at the intersection of the old Roman road linking Dreux to Mortagne-au-Perche, the village of Beauche once had on its territory the seigneury of Beaumarchais, fief of the Gués family from the 11th to the 18th century, protector of the parish. To this end, the Saint-Martin church was the subject of a donation by Foulques des Gués to the abbey of Saint-Père de Chartres in 1090. The building is oriented and includes a nave extended by a semicircular apse. The nave was flanked, at the end of the 15th and the beginning of the 16th century, by two side aisles. The northern one, very narrow, is covered with lean-tos. On the other hand, the southern aisle constitutes a second nave of three bays. It was made of flint with chaining of soft limestone and cut sandstone. The nave, the choir and the north aisle are covered with an exposed framework. The south aisle is vaulted with ribs and each of its three gables is pierced by a semicircular bay decorated, inside the splays, with the coat of arms of the Gués family. The large axial window in flamboyant Gothic style was walled up, probably in the 18th century, in order to erect the altarpiece of the high altar. The west façade is pierced, in the centre, by a semicircular portal underlined by rubble cut from the grison. On the right, a rectangular door opening onto the south aisle is surmounted by a lintel in soft Vernon limestone, decorated with elegant plant motifs, supporting a cartouche topped with a triangular pediment and framed by urns. This element could be a reuse of a funerary monument. In 1889, the large half-timbered porch that sheltered these two portals was removed. Like many churches in Thimerais, the tall hexagonal spire of the bell tower, covered in slate, rests on a solid wooden framework at the entrance to the nave. Inside, the quality of the furniture contrasts with the rusticity of the construction. The high altar and the two side altars offer a beautiful decorative ensemble from the 18th century: twisted columns with vine branches, with Corinthian capitals supporting a cornice with a broken pediment, crowned with angels framing a niche decorated with a statuette of a saint. For the repair of the masonry of the nave, transept and bell tower, the roof and framework of the bell tower, for the repair of the plaster, the Sauvegarde de l’Art français granted a grant of 120,000 F in 1998.