Whoops. You’re right, sorry. Have both…
Just for the record “Xanadu” did exist, but the name is more commonly rendered “Shang Tu”. It’s in my edition of “The Travels of Marco Polo”, and you can find it on old maps of China. I doubt if it lives up to the rep the poem gives it. There’s probably something about it in the book The Road to Xanadu, which traces the things that influenced Coleridge. Finally, Dave Barry once mentioned “Shang Tu” in one of his columns, which pretty much proves (as if it needed proving) that the “transcendaentally churish” front he puts up is, indeed, a front.
Personally, I’ve always found the person-from-Porlock story a shade too pat, given that the poem is (at least partly) about the process of creation and the difficulty of recapturing inspiration once the moment of vision is gone.
It all just seems to dovetail a little too easily, I think.