The Duchy of Normandy, which they formed by treaty with the French crown, was a great fief of medieval France, and under Richard I of Normandy was forged into a cohesive and formidable principality in feudal tenure.
O Ducado de Normandía, que se formou polo tratado coa coroa francesa, foi un gran feudo da Francia medieval e baixo Ricardo I de Normandía forxouse nun principado unido e formidable na tenencia feudal.