A Modern User's Guide to Fortification #2

Part 1 Here
Part 3 Here

Next up, it's the fortress.

The fortress is similar to a concentric castle design, but with added elements from Middle-Eastern architecture. When crusading knights took a fortress in the Middle East (in what is now Syria), they took some leaves from the enemy's books, and ended up with this:

Notice the fact that it has multiple sets of walls, like a concentric castle, and things are built into the walls, like a concentric castle. So then, what's the difference? A concentric castle is designed to be adequate living quarters for a feudal lord - a fortress isn't - in the case of Krak Des Chevaliers (as seen above) the only people living there were members of the Knights Hospitaller Order, who were primarily monks and warriors.

Fortresses are useful for defending something, and they will do that job exceedingly well, but don't expect comfortable living conditions, and watch out for cannon.

Now for the Walled Town or Palace

A simple way of defending something, and an ancient method, but particularly prevalent in the late middle ages, as it's cheaper to build a few sets of walls round the thing you want to defend than build a castle, and it's easier to update the defences to deal with new threats.

In summary, cheap, quick to build and does the job. Won't provide accommodation for your troops though, and won't stand up to heavy punishment from siege engines for very long.

Moving out of the medieval period, we see the emergence of the Star Fort

With the emergence of cannon, large, stone castle walls become impractical and ineffective. So architects take a tip from the Romans, and build forts with earthwork embankments, in star shapes. Yes, star shapes.
This wasn't just some weird obsession of architects of the time, or even a fashion thing, but a purely practical, and quite effective idea. Building bastions, revetments and redoubts allows the defenders a larger arc of fire, and a larger range, while creating "kill zones" of enfilliading fire, allowing the defenders to trap and  slaughter enemy troops easily.

There aren't many weaknesses to this design, in fact variations on it are still used today! (the first ones were built around the early 1500's) It's useful for defending most things, and can be easily adapted, as well as providing secure accommodation for troops and their equipment.


Part 1 Here
Part 3 Here