 Next, the Sully family, of the Loire Valley, came into possession of the castle for over a century in a period wherein the castle became an important base from which to harass the English during the Hundred Years' War.After the French defeat at Poitiers in 1356, it became the only castle in the region to remain in French hands.Similarly, it lost all military importance with the French victory at the end of the Hundred Years' War.