i find most of the rules for mass combat to be long and drawn out so i came up with this:
THE QUICK AND DIRTY MASS COMBAT SYSTEM (designed for 1e but compatible with all)
a player rolls a d20 twice. if they roll a 15 or higher they re-roll. the first roll is the honor roll and the second is a glory roll. the honor roll determines survival for that round and the glory roll determines the nature of the death, if they did something really amazing on the battlefield and so on or so forth. before all this happens, the dm rolls a d20 to determine how many rounds combat lasts, and a d8 to determine victory or not. 4 or lower results in defeat, 5 or higher results in victory. 1d4 or 1d6 can be used to determine force losses, either in the tens or hundreds or (if you choose) thousands. i hope this was comprehensive enough, my players like this system alot. it moves the game along nicely and allows players to dump a character they are tired of. also, many armies have clerics, so your pals will have a chance to get you resurrected, provided they can find your body....(65 or lower on d%).