The Lord Ynix’ba looked down his long nose at the prisoner. “I find you guilty of stealing the Five Sparkling Dragon Stones of Zenthibon.”

The prisoner shook his head frantically. “No! No, my Lord! You don’t understand! There was this witch, you see, and she—”

“Guilty!”

The prisoner’s shackles rattled as he collapsed to the ground, sobbing. His crying was so loud that Lord Ynix’ba had to wait several minutes before announcing the sentence. The lord tapped his foot impatiently and played with the jewels in his bracelet.

Finally the prisoner was reduced to sniffles, and that was when Lord Ynix’ba spoke again. “I hereby sentence you to the maximum possible punishment—twenty years in Zenthibon Prison!”

With fresh wails, the prisoner was hauled away.

Okay, it’s your fantasy world. If you want to throw your criminals in prison, that’s your affair. But I urge you to think carefully before tossing those poor souls into cells and throwing away the keys.

The truth is, prisons are mostly a modern invention. Incarceration has been used for many hundreds of years, but rarely as a form of punishment. People were locked up in jails (or gaols, if you please) and in institutions such as poorhouses and workhouses, but the primary purpose of locking them up was to hold them until their trials. That’s still one of the main reasons people are kept in jails. Prisoners might also be locked up because they couldn’t pay their debts or because they were destitute and couldn’t support themselves. Again, though, punishment was not the main goal; they were sort of being held as collateral for their own debts.

So how were people punished? For more severe crimes, they were usually executed. Sometimes quickly, sometimes slowly and painfully. Almost always in public. In fact, executions served as a form of entertainment in times and places where entertainment was in short supply.

For less severe offenses, there were other options. Public punishments were common—think stocks and the like. The criminals would face a period of public scorn and humiliation before returning to their homes, families, and livelihoods. Corporal punishment—i.e., physical punishment—was also widely used. Flogging, branding, maiming, etc. Criminals could be made to pay fines. They could be sentenced to slavery or other forms of servitude. They could be banished. When Europeans were colonizing the New World, sometimes criminals were sentenced to transportation, which means they were forcibly taken to America (or later, Australia), where they had to work for a certain number of years before being freed.

But imprisonment—incarceration as punishment—was very uncommon. Why? Well, it’s expensive, it removes the prisoner from the workforce (which perhaps sends his family into poverty), and it keeps the bad guys behind walls, where their punishment isn’t visible and therefore might have little deterrent effect on the rest of society.

Prison as a punishment didn’t become popular until after the American Revolution, when it was touted as a humanitarian reform. “Keep miscreants locked up by themselves,” the argument went, “so they have time to reflect on their wrongdoing and reform themselves. Allow them to be penitent.” Yes, that’s where we get the term penitentiary.

Nowadays. of course, we lock people up all the time, especially in the US. But if you’re writing a historical set before the 18th century, prison probably shouldn’t be the fate of your criminals. And if you’re writing fantasy, sci-fi, or other kinds of speculative fiction, you should think carefully about whether prison as punishment makes sense in your world.

As for Lord Ynix’ba, if he’s decided that stealing those eggs was truly a big deal, our miserable prisoner will likely be fed to the orcs instead.