Welcome to the History Extra podcast, fascinating historical conversations from the makers of BBC History Magazine.

At the end of the 17th century, a Swiss physician diagnosed his patient with a deadly new disease, nostalgia. In her new book,

Agnes Arnold Forster explores the surprising cultural history of this emotion, from

nostalgia for a lost East Germany to the 2000s revival of all things Middle Ages. I spoke to Agnes to find out more. Thanks so much for

joining me, Agnes, to talk about your new book, Nostalgia, a history of a dangerous emotion.

Nostalgia seems fairly simple on the surface, but as your book reveals, is actually a pretty

slippery concept. So before we go any further, how do you define it?

Well, I think most simply, nostalgia is a kind of fond, wistful feeling about some period in the past.

So that might be something that you've actually lived through,

but it could also be a period in history that you have an experience, you know, before you're alive.

And it generally feels nice, like it's a positive feeling. But there's a kind of twinge of loss and regret.

It's a kind of bittersweet feeling, I think. And how far back do you trace the story of nostalgia?

So the story of nostalgia begins at the end of the 17th century when a Swiss physician called Johannes Hofer wrote his medical dissertation.

So he was just doing a degree in medicine and this was his final year thesis and it was a dissertation on nostalgia.

And he was very anxious that his medical peers hadn't been paying enough attention to what he saw as a potentially deadly disease, a deadly disease that he called nostalgia.

And so obviously his version of nostalgia is very different to the one that I've just defined.

Yeah, so listeners at home might be quite surprised

to hear about the idea of nostalgia being a deadly disease. Can you tell us a bit more about

the early ideas of nostalgia? Absolutely. So Hoffa's idea of nostalgia was not so much time-based,

so not so much of kind of longing for a distant time, but a place-based

feeling. So a kind of homesickness, basically. But it wasn't just homesickness, it was a

pathological homesickness, a deadly emotion, basically. And sufferers would have sort of psychological

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