Forts are often described with words like impregnable, unassailable,
grim, invulnerable, and redoubtable. These descriptions often came
about because of their armaments. A strategically positioned fort with
a full complement of weaponry would be a problem for any invader,
because the fortress, unlike naval ships, provided a stable platform
upon which guns could be mounted and trained on the enemy. Anyone
approaching within approximately 500 yards would be in great danger,
even though the artillery in those times was not always accurate and
aim was extremely difficult.