The Perfect Heresy  (English, Paperback, O'Shea Stephen)

Eight hundred years ago, the Cathars, a group of heretical Christians from all walks of society, high and low, flourished in what is now the Languedoc in Southern France. Their subversive beliefs brought down on them the wrath of Popes and monarchs and provoked a brutal 'Crusade' against them. The final defeat of the Cathars was horrific with mass burnings of men, women and children in the village of Montaillou in the Pyrenees.