Rules for Minions/Mooks

[Saint]

I'd like to pick the collective brain of the forum.

Seems like the trend in rpg systems is to make minions, mooks, henchman, and other lower tier npc's easier to eliminate in combat than the more important adversaries.

I'm trying to nail down just when this started. My question is: what's the earliest set of rules you can remember that advocated this approach?

Thanks in advance.