I’m getting close to being halfway through with book 2 in the Rydding Village series, and I’m having to make some decisions about how to handle the worldbuilding. There’s a balance between realism and fantasy in any secondary-world fantasy — that is, fantasy that’s not set on our earth. I’ve come to think of this as the Potato Problem.

There’s something about a potato that makes it seem like it should fit in an old-fashioned world. Potatoes roasted in an open fire are so simple and basic and the kind of thing you might eat while on a fantasy quest. Except potatoes didn’t become common in Europe until the late 1500s because they’re originally from South America. Your medieval peasant wouldn’t have been roasting potatoes in the fire or having potatoes in a hearty stew, even if Medieval Times (a sort of dinner theater in which you eat a Ye Olde Meal while watching jousting) serves roasted potatoes.

But can your characters in a fantasy world based on medieval Europe eat potatoes? That’s a tricky question. The really pedantic people who know history (like me) are likely to get thrown out of the story by a mention of potatoes. But your world could be one in which potatoes grow in the continent where your characters live, since it’s not our earth. Or people from the continent where your characters live could have traveled to the place where the potatoes are earlier than they did in our world. The big question is whether this detail will add to your world or detract from it. There’s something cozy and homey about a potato that just seems to fit, but you also don’t want to sound like you don’t know what you’re talking about.

It’s an issue that has come up even for Tolkien, who was a medievalist who probably should have known about this, but the hobbits in the Lord of the Rings books eat potatoes. I actually think the hobbits don’t seem all that medieval. Their costuming in the films seems sort of 18th century, when potatoes would have been in England, and that costuming fits the descriptions in the books, which refer to things like waistcoats and buttons. In behavior, the hobbits strike me as Edwardian gentlemen. It’s only the other societies in that world that seem medieval. The hobbits did have to explain “taters” to the others, so maybe they hadn’t spread that far.

I’m going with a roughly 17th-18th century level of technology in my world (aside from gunpowder, which I don’t think they have), so potatoes would be a possibility, even for Europe in our world. I haven’t decided yet whether I’m going to use them. This actually came up when I was thinking about how I would make a particular pastry mentioned in the book, and the dough that would be most suitable for it contains potato flour (or potato flakes). I’d probably not mention the ingredient in the book, but if I provided a recipe it would have potatoes, and would that be a problem?

There are similar issues relating to tomatoes, which come from the same place and came to Europe at about the same time. You might find tomatoes in Italian food starting around the 1600s. Tobacco and corn also came from the Americas.

Then there’s the issue of language. Can you use words based on proper nouns from our world in your fantasy world? Can you put your feet up on an ottoman (named for the empire) or eat a sandwich (named for the earl) when those people and places don’t exist in your world? Or do we assume that the whole book is being translated to modern English, and those words are the nearest approximation in our language to what they’re saying in the language of that world?

And this is probably getting way too nerdy. Most readers only notice if the world seems real and believable to them. Only a few weirdoes are going, “Ha! Potatoes!”