Under what alias was Rowling credited as the author of Quidditch Through the Ages?

Rowling was credited as Kennilworthy Whisp for Quidditch Through the Ages.

Quidditch Through the Ages is a fictional reference book about the wizarding sport of Quidditch. In the Harry Potter world, Kennilworthy Whisp is presented as the book’s author, while the real-world publication credits J.K. Rowling as its creator.

The book was published in 2001 alongside Fantastic Beasts and Where to Find Them. Both were issued as charity tie-ins, with proceeds supporting Comic Relief. The fictional presentation made the volumes resemble books that Harry and his classmates might use at Hogwarts.

Kennilworthy Whisp is therefore a pen name used within the book’s framing device, not the name of a real independent author who wrote the work. Newt Scamander is another fictional author associated with Fantastic Beasts, which is why the two names are sometimes mixed up.