The 22nd annual conference of the Wartburg Society for the Research of Castles and Palaces e.V., held in collaboration with the German Society for Fortress Research e.V. in 2014 in Schwerin, focused on the transformations of military architecture under the influence of firearms between the mid-15th and the early 17th centuries. The contributions in this conference proceedings examine how noble and territorial castle owners responded to the challenges posed by artillery. What concepts did they pursue, who employed which architectural forms, and who adopted the new bastion style from Italy, and when? Did this development truly lead to the end of castle construction, as is often claimed, or even to a separation between purely military fortresses and supposedly more habitable unfortified palaces? The discussion includes both international and regional development trends of the early period.