^interesting! 1) a lot of people died in the black plague, which
  only lasted a few years. 2) All the money from the dead people
  had to go somewhere, so the few that were left over got very
  very rich 3) They needed stuff to spend their money on - clothes
  are always good. 4) Those who weren't rich - the peasants, made
  lots and lots of linen out of flax (which is cheap and easy to
  grow anywhere) 5) Lots of linen, lots of disposible income -
  suddenly, UNDERPANTS are invented. 6) Old underwear had to go
  somewhere, so the guy that used to collect bones after the black
  plague, now collected old underpants, which there was a lot of.
  7) Mills got them for free, so they decided to make: PAPER. Lots
  and lots of paper. 8) a decent printing press was born 9)
  Information revolution. Out of old underpants. Love it. oh! that
  was the interesting part: the underpants happened in the age of
  properity AFTER the black plague was over. 40 million died. The
  survivers, who were perfectly fine, got the money (relatives,
  etc) from those who died, so there was a generation of "noveu
  riche". The underpants were born simply because they had more
  money than they knew what to do with - so why not cover the
  naughty bits? Underpants get discarded after a time, and instead
  of wasting good linen, turn it into a pulp, make paper. Free
  paper easily available = lots of stuff to print on. gutenberg
  invents movable type - bingo, free paper, flexible printing, new
  educational information coming from the greeks who ran off after
  the fall of constantinople and immigrated (that's where the "new
  old greek stuff" all came from in the Rennaisance... all a neat
  chain of events that happened within a few short years.