For the first several centuries of its existence, the Château de Billy was the property of its builders, the Bourbons. The fortified town of Billy and the province of Bourbonnais were part of the domain of the lordship of the Bourbons. Both the castle and the lordship remained powerful until the French Revolution (1789).
Architecture
The main fortification has an ovoid layout with a hexagonal watchtower which dominates the houses of the town and the medieval streets that curve around the walls of the castle. An imposing châtelet guards the entrance. The southern curtain wall has a walkway that offers a splendid panorama of the Allier valley.[2]