Homer Nods

The New Yorker is famous for its fact checking "et idem indignor quandoque bonus dormitat Homerus."  Here's Rebecca Mead writing about Daphne Guinness (subscription only) in the September 26, 2011 New Yorker (my emphasis)

[Guinness] often wears a veil: "What's great is tying a bit of net around your face, and everything looks like it's in Super 8. It gives a bit of grain to the world." Even before J.K. Rowling came up with the idea, Guinness dreamed of wearing a cloak that would render her invisible.

What? Anyone over 25 with a bit of D&D in their misspent youth—or anyone who's read some Tolkien—knows that J.K. Rowling didn't invent the cloak of invisibility. Here's a version from Emily Watson's book Fairies of Our Garden

This book was published in 1867.  That's a few years before Rowling could have "c[o]me up with the idea."