There's a scene in my first novel where the main character, a nurse, sweeps herbs over the hospital floorboards in an attempt to mask the smell of the patients. It's no big deal; just part of what she happens to be doing at the time, but several readers have mentioned it as a fascinating historical detail; an example of how carefully I must have researched the era.
But the truth is... I, er... made it up. I don't know whether it was routine practice for 18th-century hospital staff to spread herbs on the floor – but equally, there's nothing to say that one resourceful individual in one hospital wouldn't try it out.
Is this, therefore, historically accurate or not? I believe it to be authentic – herbs were around then, brooms were around, smells were around, it makes sense to use the former to deal with the latter. But what if someone, having read the book, starts telling their friends the interesting fact that 'in the olden days, hospitals used to put herbs on the floor!' Is it unfair on readers to make them believe in something when it's just an illusion?
Personally, I don't think it's unfair at all – history involves a lot of individuals doing individual things, and sometimes those individual things aren't what a GCSE history book says 'the Georgians' (or whoever) homogeneously did. In fiction, what's important is whether something is possible and believable within the context of the time.
In a recent piece for the Guardian, James Forrester pointed out a mistake in an un-named book set in the 14th century – the narrative mentioned that there were 'no priests within a three-day ride,' and Forrester's knowledge of history enabled him to work out that there would in fact have been several thousand.
Now, I don't know what this book was, and chances are the author really couldn't be arsed to get the facts right, but unless the story has a modern, omniscient narrator, then it's being told from a historical point of view – the point of view of someone living in their own version of 'now'. I don't know about you, but in my 'now' – the 21st century – there is an awful lot of stuff I'm unaware of and an awful lot of stuff I get wrong. Should a 14th century character really be expected to have accurate details about every single thing that is going on in their 'now'?
Maybe the narrator has no idea about the priests, but makes the statement anyway so as to appear authoritative. Maybe they've been told this by someone with an ulterior motive, and are naïve enough to believe it. Or perhaps the statement is an intentional teaser for knowledgeable readers; a hint that something is amiss and that the narrator has intriguing reasons for giving the wrong information. Maybe it's a way for the author to conspire with his or her audience, and reward the alert ones with an extra clue to the mystery.
Readers are quite entitled to enjoy feeling clever when they perceive historical inaccuracies, but there's also a danger of congratulating yourself so much that you miss out. If the 'mistake' turns out to be an early warning of the political machinations that ultimately endanger the hero's life, then it's even cleverer – and more satisfying – to have used your superior knowledge to work that out.