It was the first I'd heard of it.
Now, I don't have the greatest memory in the world, and I sometimes lose track of what I've said yes to, but I thought it was rather unlikely that I would lose a whole convention, especially one in a country I really wanted to visit and had not yet gone to.
So I emailled my agents and assistants and asked if any of them knew anything about a convention in Moscow in 2008. None of them did. I searched my hard disk for mentions of Moscow and Euroscon, and found nothing at all.
Still, there it was and is up at http://www.convent.ru/Euroscon/. The first two Guests of Honour listed were George R. R. Martin and Neil Gaiman. Luckily, George is an old friend, so I wrote to him and asked if he could shed any light on this. He wrote back to say,
This is news to me.
My calendar for 2009 has been set for some time, and
Moscow is not on it.
Not that I wouldn't like to visit Russia some day,
mind you... but unless they plan to kidnap me, I won't be there.
I hope our clones have a good time at the convention.
I'd really like to go to Moscow, but many years ago, when a convention announced me as a guest, then asked me, then told me when I explained I couldn't go as I had a prior committment, that they'd because already announced me as a guest that they would announce now that I'd unexpectedly pulled out, and it was pretty much an act of blackmail, back then I decided that if a convention announced me as a guest before they asked me that I'd simply and automatically say no.
So when I do go to Moscow, it won't be for Euroscon, I'm afraid.