The lordship of Valmont belonged to the powerful family of Estouteville. It claimed as its founder Stoot, a companion of Rollo, who in 911 had received the lands of Gallemonte taken from the public domain by the first Duke of Normandy.
Robert I d'Estouteville was at the end of the 11th century one of the loyal followers of Duke Robert Curthose who he accompanied in 1096 on the crusade. In 1105 was the fratricidal war that set Henri Beauclerc, king of England, against Robert, Duke of Normandy. At this time Robert d'Estouteville, wrote Orderic Vital, reinforced his castles in the lands of Caux. It is thus probable that he replaced the earth and wooden fortifications of Valmont, with this solid stone keep.
But Robert d'Estouteville was taken prisoner in the following year on the field of the battle of Tinchebray and ended his days in an English prison.
The keep at Valmont belonged to the family of Romanesque keeps of which Henri Beauclerc was a proponent in Normandy in Caen, Vire, Domfront, Falaise, Arques, etc. A square ground plan, thick (2.4 m) and high walls (22.1 m), reinforced at the corners and on each face by flat buttresses primitively supporting a wooden gallery at the top, the use of stone (the local tufa limestone mixed with banks of flint arranged in the fish bone pattern), three internal floors and the access door on the first floor.
The keep was restored after the Hundred Years War, in 1458, by Louis d'Estouteville who pierced lattice windows, added machicolations and a high four sided roof. Subsequently Jacques d'Estouteville and his wife Louise d'Albret included it during the 1470s in a brick and stone fortress, with truncated surfaces, in the style of Louis XI, before Adrienne d'Estouteville finally added to the castle a Renaissance wing in 1550. 

Bernard Beck

Bibliography

- Gabriel de la Morandière : Histoire de la Maison d'Estouteville en Normandie. Delagrave, Paris, 1903. 
- O.M. Lannelongue : Le château de Valmont. Plon, Paris, 1908.