

What Makes a Bastion

While the fire from one cannon may have an effect, fire from two on the same attacker would have a improved chance of scoring hits. From three - or four - even better! With bastions sticking out from the core of the fort, cannon mounted on them could not only lay down overlapping fields of fire but also intersecting fields of fire from two neighboring bastions. The enemy could be caught in a crossfire. Plus, should a cannon or two be silenced, defenders still could cover the field before them.

The successful bastion not only protected itself from every place an attacker could strike it but also its adjoining ramparts and - very important - neighboring bastions. The mutual support of bastions, with one being able to lay down protective fire for another, was why this concept became so successful and so widely adopted. What an observer immediately notices is the arrowhead-like shape of the bastion, with straight sides, not curved. Straight sides allowed fire to be directed by defenders along any portion of its sides and out onto the ditch and ground beyond; there was nothing sticking out to interfere with lines of fire, no places to shield attackers. If attackers at the base of a wall or tower could not be reached by defensive fire, then they could be free to tunnel under to undermine or set explosives. As mentioned earlier, the round tower of the medieval castle/fort did leave blind spots for defensive fire. But a bastion with incorrectly angled sides also afforded protection for attackers.