Prelude: Dangers of Magic
So, you decided to add magic to your world. Congratulations, you messed up majorly: the easy way available to the writers of historical fiction, e.g. fully copying a historical world, was just lost for you. Poor soul! (not really, you will work it out eventually)
Let’s repeat it proudly together. Is it fantasy? No historical guidelines can work anymore.
It’s obvious if you went all-out and created a “high magic” setting, where magic is not only real, but also easily accessible to even the most common folks. We don’t have any historical records on how much potionbrewer asks for their services, we don’t have any idea how prevalence of healing spells would influence child mortality, and we don’t even imagine what kinds of technical-magical hybrids can an enchanter with a talent for mechanics create. These worlds will be nothing like our Middle Ages.
Maybe you started by playing safe and declared it a “low magic” setting: magic may be real, but so rare most people never seen it. Maybe magic is weak, maybe it is very specialized and useful only for battle. It’s easy to decide that the lives of common folk would not be that different from true medieval simply because there are whooping ten people in the kingdom able to wield magic. Well, we are in for a rough ride.
If you haven’t done so before, read Yudkowsky’s guide to intelligent characters and try to think like a real munchkin in your fantasy world: munchkinism is what made our civilization great, not roleplay or traditions.
Even deliberately overly specific, rare, weak magic can and will be exploited, drawing your world away from the mundane history: medieval or modern technology is not the simplest or most optimal solution, it’s the solution we developed because there was no better alternative.
Imagine that all you do is allowing a small introductory-level spell to be cast by one person per thousand. Is this a sufficiently small change? Yes. Will it change the medieval landscape dramatically? Yes! A small chance to be fried by a lightning will revolutionize knight armor and make uninsulated metal weapons much less common among the wealthy warriors; they would be stupid to risk getting killed by an unblockable spell otherwise. Or just try to imagine what a mage able to cast five Lightning Bolts per day could do to metallurgy (hint: humanity took until XIX century to mass-produce aluminium not because it’s useless). Would he? Usually being an exclusive supplier of miraculous products not only pays better than war, but also has a notably smaller chance to have your head bashed.
If more mundane magical gifts are easily usable by some highly limited group, it goes even worse. Have you ever wondered about yields of non-magical crops wood elves with a minor affinity for understanding plants could reach? Or the quality of steel an average tiefling blacksmith (fire resistance comes as a racial bonus) could produce? Or imagine how much more effective a vampire with blood sense would be in healing than an average person only able to guess what happens inside the patient’s body? While vampire doctors may still like bloodletting just as much as their historical counterparts, they at least wouldn’t believe it helps your health.
Even a “low magic” setting would be very different from the true Middle Ages. “High magic” will simply burn and vaporize every smallest bit of your medieval intuition.
Is there a cure? Yes, we could always start from the very base and build the whole world using the parts of real history that are still relevant.
