The rich and tumultuous history of the castle not only sheds light on the history of Gascony between the 12th and 14th centuries but also on the Hundred Years' War, in which the fortress played a significant role. It was built by Henry III Plantagenet, the King of England, around 1230-1250, on the site of an earlier tower constructed in the late 12th century by Richard the Lionheart.​

​

It was fiercely contested between English and French soldiers during the Hundred Years' War (1337-1453). One of the most well-known sieges of Château des Quat'Sos is depicted in "The Accursed Kings," the famous historical fresco by Maurice Druon. In the late summer of 1324, for the fifth time, the French armies besieged the castle. They experimented with a new weapon, the "fire-breathing mouths" (cannons)...