The great chemist Sir Humphry Davy thought that Saturn was inhabited by super-smart creatures with wings made of "extremely thin membranes ... azure and rose-colour".
If a leading 19th-century scientist could believe in fairies, what about Shakespeare, a man with an unparalleled imagination, several hundred years earlier?
In Romeo and Juliet, we hear about Queen Mab, whose very name is a dirty joke, since "quean" and "mab" were both slang terms for tart.
She is "the fairies' midwife", "no bigger than an agate-stone", who is driven around in "an empty hazel-nut" by "a small grey-coated gnat". She gets up to a variety of tricks, tickling parsons' noses, plaiting horses' manes - and teaching girls about sex.
And in A Midsummer Night's Dream, Shakespeare brought Oberon, Titania and their entourage on to the stage.
So did he think such fairies might really exist? And, if not, what was he doing putting them in his plays?
On 22 April, on the eve of the Bard's birthday, a leading Shakespearean scholar will attempt to "recover the ways in which popular magic was regarded in the age of Shakespeare".
Michael Hattaway, an emeritus professor of English literature at the University of Sheffield who now teaches at New York University in London, is delivering the 100th annual British Academy Shakespeare lecture.
The lecture, "'Enter Caelia, the Fairy Queen in her night attire': Shakespeare and the Fairies", will take in stories of fairies conscripted to work in coal mines and real-life protesters who called themselves "servants of the queen of the fairies" and who painted themselves as "fairies" to poach the Duke of Buckingham's deer.
Professor Hattaway said he would explore the long-term influence of Shakespeare's fairies through whimsical and creepy paintings that portray Queen Mab as everything from a demon to a guardian angel, a bringer of dreams to a fashionable busybody.
It is not known whether Shakespeare believed in fairies or simply thought them a quaint superstition, but Professor Hattaway said it was possible to say what he was using them for: as "a way of portraying inwardness and dreams".