The Poor of Lyons, whom their detractors called Waldensians--after the name of their founder Waldo (or Vaud?s)--first emerged around 1170 and formed a sect that embraced evangelism, prophesy and poverty. Challenging prohibition by following the Scripture to the last letter, they were condemned as heretics. The Waldensians constituted the only medieval heresy to have survived to the dawn of the so-called modern period. Their tale of simple devotion...