It's very possible that many people in medieval times didn't know how to start a fire. Do you? I mean without a match or lighter. Maybe you do. You've probably seen at least one person do it on TV.
But they didn't have TV. They also didn't have matches or lighters. But they did have fire.
So why would I make such an absurd statement?
Most people didn't need to start fires. Even though they used fire for many things we use modern technology for today (light, cooking, heat, etc.). Did they go without all this? No. They just didn't let their fires go out. They kept the coals burning.
In the early religion of India there was one person assigned to never let the fire go out. Other people had little containers that they used to carry embers around in when they were traveling. Fire was a big deal. Someone had to know how to light it, but most people may not have. (Check out this video for fun.)
Even if you're good at it, lighting a fire is not easy.
It's the same thing with writing.
If you stop writing for a while, it's hard to start. If you keep yourself in practice, then you've got an ember of the writing skills still kicking around in your brain. A few minutes a day is enough to keep the embers glowing.
But you don't want an ember. You want a ravenous flame that keeps those pages lit with wonder time after time. So write a bit each day. Keep your embers hot. And when you're ready, coax your little flame into something greater. Because professional writers write. They write a lot. Their writing flame catches on to all sorts of things....Come to think of it, perhaps a fire analogy wasn't the best choice when talking about books.
Ah, well. Keep up the writing. Don't let it go out. Because just like fire, it's more difficult to start all over from the beginning.