The moats and turrets ' though Gothic in style ' are purely decorative, and the staircase is noted for its innovative straight flights and landings rather than the old spiral form that was designed to fend off invaders.
The staircase was designed as a hidden defensive instrument against the invaders.
mnli hypothesis: The staircase was designed as a hidden defensive instrument against the invaders. premise: The moats and turrets ' though Gothic in style ' are purely decorative, and the staircase is noted for its innovative straight flights and landings rather than the old spiral form that was designed to fend off invaders.