The extension stands on two basement floors, not visible from the courtyard but necessary because of falling ground to the river Nogat. The lowest has narrow openings, now bricked up, while that immediately above was used for storage with larger square windows set in brick frames. Above was the Chancellery, at ground level when approached from the courtyard. Its large stone windows are separated by brick buttresses in the primary south and west faces rising the height of the building to support the embattled wall-walk (Fig 9). The floor above was devoted to the Grand Master's apartments with the elaborate windows that fill the recesses between the brick buttresses marking the principal reception rooms. The two-light upper windows are set in brick frames and the three-light lower windows in stone frames with