There are several places called Fort George across the world, and two in the UK. I’m not writing about the one in Guernsey today, but rather the one in the highlands of Scotland. It’s not technically a castle because it is a military installation, and was never intended as a high-status residence, but it’s interesting enough that I thought I would bend the rules a little.
A New Kind of Fortress
When gunpowder weapons were first developed they had many benefits, but they lacked the power of a trebuchet. Sieges therefore remained as they pretty much always had done, only with more smoke and loud bangs – cannons were primarily an anti-infantry weapon, and thus useful in defence but not really in bringing down a castle wall. Castle designs changed somewhat to accommodate gunpowder, and where one once would have seen arrow slits castles were being built with gun loops and cannon ports.
Over time, though, cannons got more powerful, and were able to make big holes in stone walls. The mobility and relative accuracy of cannons made the old castle designs far less useful and so designs changed. Clearly the walls needed to be thicker and better able to absorb impacts, so earthen ramparts were used. The previously popular round towers were problematic for related reasons – a large bomb called a petard could be comparatively safely placed at the base because there was an area which could not be easily seen from anywhere inside (to be hoist on one’s own petard was to be blown up by one’s own bomb – they were also, more dangerously, used to blow open gate houses and portcullises). Because of this bastions were built which were angled and protruded beyond the walls in such a way that they allowed a clear field of fire across the entire area.