The Château de Langeais is a medieval castle, rebuilt as a château, in Indre-et-Loire, France, built on a promontory created by the small valley of the Roumer River at the opening to the Loire Valley. Founded in 992 by Fulk Nerra, Count of Anjou, the castle was soon attacked by Odo I, Count of Blois. After the unsuccessful attack, the now-ruined stone keep was built; it is one of the earliest datable stone examples of a keep. Between 994 and 996 the castle was besieged unsuccessfully twice more.