♜  The town of Gaillon was a border territory, disputed throughout the Middle Ages, between the Duchy of Normandy and the Kingdom of France, a first ducal castle is already attested in the eleventh century. The site was attached to the crown of France by a treaty in 1195; it then passed into the hands of various owners before being sold in the 13th century by King Louis IX to the archbishop of Rouen, who made it a summer residence. But the conflicts between the kingdoms of France and England resumed and the castle was again put in a state of siege and defense; its demolition was finally ordered in 1424 by the Duke of Bedford.

The current castle was built on these ruins from 1455 onwards by the archbishop of Rouen, who wanted to build an Italian palace. He thus made Gaillon the first Renaissance castle in France. Gaillon was embellished and enlarged over the years, then sold during the Revolution.

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It became in turn a detention center (1812-1901), a garrison barracks and military training center (1901-1925) before being bought in 1970 by the State, which has since committed to restore and revive the castle.