There's a reasonably well-known novel where the heroine time-travels back to Regency Britain, breaks an expensive vase, and while still in that time period hops onto EBay and buys a new one. Now if this had been in a steampunk novel with an author who was pretty good at world building, it may have worked. But as a historical setting no, no and no again. No electricity. Therefore no computers, no internet and no EBay. Also no credit cards to pay for the purchase.
But there are other common concepts that need to be avoided in historical novels too.
Until Sigmund Freud started working on the idea of psychoanalysis, you couldn't say a person made a Freudian slip. Nor could you talk about an Oedipus Complex. Sure, Oedipus had been around for hundreds of years, but the psychological premise of his complex had not. See the difference? And that's the trick about historical accuracy. Your characters can psychoanalyze each other as much as they like. But they can only do so in terms the people of that era would have used. So "That man reminds me of the character Oedipus we had to study at Eton, because…" would work.
"That man has an Oedipus Complex because…" would not.
Another thing. Please don't have characters say, "You’re welcome", unless they're inviting someone into their house, before 1907. The phrase wasn't used until then.
There's 10 anachronisms in the picture. Did you find them all?
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