The lordship of Sigournais has existed since at least 1050. It was then the property of Zacharie de Pouzauges, a vassal of the vicomtes de Thouars. In the 12th century, a priory dedicated to Saint-Saturnin was built within the walls of the castellum. Issues of cohabitation with the castle's inhabitants arose. Moreover, the current castle, built by Guyard de Sainte-Flayve, came into existence thanks to the relocation of the priory outside the enclosure.
Nothing remains visible from the ancient fortress of the 12th century; the foundations in the ground are located a bit further to the north, with the current castle covering a part of them.
The current castle, constructed under Guyard de Sainte-Flayve, dates from the late 15th century and has an almost pentagonal shape. This enclosure consists of curtain walls flanked by eight round towers and a large gatehouse tower. A dry moat carved into the limestone surrounds it all. The gatehouse tower serves as both a fortified entrance (gatehouse) and a main tower (keep). It consists of a large rectangular tower flanked by two round towers on each side, all crowned with a battlemented walkway on machicolations. The entrance corridor is divided into two entrances, one for carts and one for pedestrians. On the outside, a fixed bridge was extended by a cart bridge and a pedestrian drawbridge, side by side. Inside the gatehouse tower, there were two levels. On the first level, there was a guard room and a vestibule. Canon openings were arranged in the thickness of the wall. On the second level, accessible by the spiral staircase in the South flanking tower, there was a room serving both as a reception hall and as the lord's residence, separated by a wall was a chamber.
A large pentagonal courtyard was protected by walls and towers, crowned with crenellated battlements on machicolations, and probably served as a bailey (outer courtyard). Some buildings were attached to the ramparts, such as stables, kitchens, a bakery, forge, etc.
Saint-Georges de Boscherville Abbey is a former Benedictine abbey. It was founded in about 1113 by Guillaume de Tancarville on the site of an earlier establishment of secular canons and settled by monks from the Abbey of Saint-Evroul. The abbey church made of Caumont stone was erected from 1113 to 1140. The Norman builders aimed to have very well-lit naves and they did this by means of tall, large windows, initially made possible by a wooden ceiling, which prevented uplift, although this was replaced by a Gothic vault in the 13th century. The chapter room was built after the abbey church and dates from the last quarter of the 12th century.
The arrival of the Maurist monks in 1659, after the disasters of the Wars of Religion, helped to get the abbey back on a firmer spiritual, architectural and economic footing. They erected a large monastic building one wing of which fitted tightly around the chapter house (which was otherwise left as it was).