Where do these stories start?

[rochesteruponmedway]

No: HPFGUIDX 132629

I have just been solemnly informed that the first three books were 
written by Jo's ex husband and that he invented the name quidditch. 
Where do these extraordinary ideas come from?  This is probably old 
stuff but I was still shocked that anyone should produce this as gospel.
How am I going to answer this idiot?

Sylvia