We all know this famous sentence, bound for centuries to our city : During Béziers's sack, in 1209, the legate of the Pope Innocent III, Arnaud Amaury, asked for what to do with Catholics mixed to heretics in Béziers, would have answered :
"Kill them all, and let God sort them out".
 (the exact sentence is : "Caedite eos. Novit enim Dominus qui sunt eius" a better translation would be : "Massacre Them, 'cause God knows his")

 Nevertheless, this sentence is not quoted by any of the authors present on the scene, as Pierre de Vaux-Sernei. It appears, for the first time, in the Caesarius von Heisterbach's writings, Cîteaux order's monk from the Hesterbach monastery near Bonn.

In 1219 and 1223, two hundred lieus from Béziers, this man wrote, in the diocese of Cologne, twelve ridiculous books "Illustrium miraculorum et historiarum memorabilium" appeared in their first publishing, in 1481 , under the name of "Dialogi de miraculis") where he tells, under shape of dialog, the event (among others).

The fanciful contents of these books demonstrates the lack of seriousness this author had. By compassion, we could think he had the fault to believe too slightly not reliable people.
Nevertheless, the enormous nonsense which mark out his works let rather think he has smoked a little bit too much the abbey's carpet - quite at least, has too much used hallucinogenic potions... However, another explanation lets augur that these works were in adequacy with his time : indeed, Césaire, obsessed by the Devil, considered the Albigensian (Cathars) as limbs of the Devil.
 He attempts to demonstrate their heresy by making up real facts. For example, he reports that heretics, seeing the crusaders arriving, "urinated on the Holy Gospel's book, threw it outside the Béziers's ramparts onto the direction of the Christians and, after having shot on it some arrows, shouted "Here is your law, Miserables !".

Nevertheless, only Pierre of Vaux-de-Cernay, author of "histoire Albigeoise" in 1213, tells an event of that kind : "A night, at the daybreak, a priest of this city went to the church to celebrate the morning mass: they seized the priest, struck him with an extreme brutality and hurt him seriously by breaking his arm. Then they took the chalice and urinated inside, in defiance of the body and the blood of the Christ". This event is not however linked to the Béziers sack's day.

If we analyse the situation, Césaire uses two real events - but independents from each others - by connecting them to base his propaganda against the Cathar heresy.
 In brief, even if famous French authors resumed the statements, the evocation of this sentence - whose biblical origin does not make doubt : Timothy 2:19 or Numbers 16:5 - seems to be a pure product of Césaire's imagination, as some devils he describes, playing soccer with ball rolled souls...