I think someone mentioned Selene was only 600 years but I remember the date in the second moive of 1216 which they showed her about to be embraced, so 800 is much closer.
The more I think about it the tougher she sounds, 800 years of killing Werewolves as her job, CRAP!
You would have to be a BadMoFo to last 800 years doing that week after week.
