Their raids were quick and deadly. Skilled navigators, they managed to sail up the rivers in order to quickly reach the cities and attack them by surprise. If, at the beginning, they attacked the coastal regions, their incursions were made further and further inland.
Towards the middle of the 9th century, the Vikings' ambitions changed. They have the project to install colonies within the Frankish kingdom. Paris was besieged several times. Indeed, the country suffers from both a dying economy and a great insecurity due to the multiplication of Norman raids.
In 911, the signature of the " Treaty of Saint-Clair-sur-Epte " marks the birth of the County of Normandy led by Rollon who took the title of Jarl of the Normans.
La Motte Féodale
"Concerning our motte, it is quite typical of the fortifications that appear at the end of the 11th century. Thus the ducal motte castles of Gisors and Château-sur-Epte were built in 1097. Later on, other mottes were built during the first quarter of the 12th century, notably during the war between Henri I Beauclerc and his brother Robert Courteheuse in 1105-1106 or during the French invasion of part of the Vexin in 1118-1119 or during the revolt of the barons against Henri I Beauclerc in 1123-1124.
It is therefore possible to hypothesize that the small castle of Mesnil-Jourdain was built at this period. It seems that this type of fortification is no longer built in our region after the middle of the 12th century.
It is therefore interesting that the toponym and the typology of the fortification are in agreement.