They were meant to be impenetrable, these medieval symbols of power. Castles were difficult for attackers to take by assault, so sieges and starvation were usually their strategy. What measures did castle inhabitants take to survive year-long sieges? How effective were catapults, like the notorious trebuchet, known as an “instrumentum diabolicum”, or “instrument of the devil “? And what role did psychological warfare play in the struggle to defend the castle? “The Fortress Castle” portrays the rise and fall of these mighty buildings. From the first early medieval super castles and the heyday of stone-built strongholds to the decline in the importance of defensive architecture as a result of new weapons technologies and political and social upheavals in the 15th and 16th centuries.