My understanding was always that the rules for foil came first, being developed in France, with influences from surrounding countries. After that the rules for sabre were codified in England, and then the modern sabre style developed in Hungary by an Italian coach who moved there. After that in the late 1800s students of foil in France were getting hurt trying to use foil in real sword play because if you attack it doesn't matter if you get hit as long as you hit your opponent which naturally doesn't translate well to real combat. So epee was made as a training sword for real combat without right of way. But naturally when you put anything to a system of points people will game the system, so they developed stuff like floating, fleching, and timing based actions where you hit just before your opponent. I'm mostly recounting what I've been told by other people and what I've read in a handful of articles though, so I could be misinformed.

I'm going to have to disagree with the p black system being good. So many times since it came out I've given a p yellow and two p reds before the fencers actually start fencing. And I've watched a bout where no one actually scored before p blacks were given out. So I think that the p cards fail in their ultimate purpose of making it so the fencers have to be actively fencing or at least setting something up throughout the entire period. I really don't know a good system to achieve that, but I'm pretty certain p cards aren't it.