Can a great person be killed?
I produced a Great Merchant, and sent him off to a distant capital (Carthage) for a trade mission.
A few turns later, Saladin and Mehmed declare war on me. I forget about the merchant.
A few turns after that, I opened up my military advisor, and the Great Merchant had vaporised!!
What happened?
Yeah, if an enemy unit moves onto the same tile (no defender or the last defender is defeated) the GP dies. I think you should be able to capture GP, as we and the Soviets divvied up the German scientists after WWII.


for mines and lumbermills (and quarries in Warlords 2.08)
and probably been written when they started developing the game (just like the Civilopedia) 

I have to warn you though that it needs updating - with regard to the rankattitude modifiers - I got them mixed up and haven't had time to change that yet...