mythago
Hero
Here are some real-world historical reasons for not killing prisoners.
1) You have to let them confess and/or convert to the One True Faith before you dispatch them; to do otherwise not just be killing an enemy, but damning their eternal souls. At the very least, you must take the time to instruct them in the basics of the OTF and to get them to truly accept it. THEN if you kill them, at least they go straight to heaven.
2) You're destroying your lord's property. Once you conquer their lands, serfs become the underlings of your lord. You don't waste his peasants (and their valuable labor) without his say-so.
3) These people have value in and of themselves, as slaves, workers, and so forth. They can contribute to the greater good with their labor much better than they can as fertilizer.
4) Revenge later. You kill all these people, their lord gets pissed and lays waste to twice as many of YOUR countrymen. On the other hand, this bunch of peasants doesn't want to risk their lives attacking you; they lost, they want to go home. You follow the unspoken rule that you won't slaughter any you don't need to. If one dumb peasant launches himself at you, you cut him in half, and the rest are better-behaved.
1) You have to let them confess and/or convert to the One True Faith before you dispatch them; to do otherwise not just be killing an enemy, but damning their eternal souls. At the very least, you must take the time to instruct them in the basics of the OTF and to get them to truly accept it. THEN if you kill them, at least they go straight to heaven.
2) You're destroying your lord's property. Once you conquer their lands, serfs become the underlings of your lord. You don't waste his peasants (and their valuable labor) without his say-so.
3) These people have value in and of themselves, as slaves, workers, and so forth. They can contribute to the greater good with their labor much better than they can as fertilizer.
4) Revenge later. You kill all these people, their lord gets pissed and lays waste to twice as many of YOUR countrymen. On the other hand, this bunch of peasants doesn't want to risk their lives attacking you; they lost, they want to go home. You follow the unspoken rule that you won't slaughter any you don't need to. If one dumb peasant launches himself at you, you cut him in half, and the rest are better-behaved.